Complete part (a) and part (b) given the following system of equations.
x-y=1
x + 3y =9
Write your answer.

Answers

Answer 1

Answer:

(3,2)

Step-by-step explanation:

Setting up equation so we can use substitution method

x - y = 1 , x + 3y = 9

step 1 set first equation equal to x by adding y to both sides so we can use the substitution method to solve the system of equations.

x = y + 1 , x + 3y = 9

now we can plug in ( or substitute hence substitution method ) the first equation into the second

Solving for y using the substitution method

x + 3y = 9

plug in x = y + 1

y + 1 + 3y = 9

combine like terms

4y + 1 = 9

subtract 1 from both sides

4y = 8

divide both sides by 4

y = 2

Now to find the value of x we plug in the value of y into one of the equations and solve for x.

Solving for x

x - y = 1

y = 2

x - 2 = 1

add 2 to both sides

x = 3

The solution would be (3,2)

Answer 2

Answer:

x = 3 and y = 2 or (3,2) in coordinate form

Step-by-step explanation:

Given:

[tex]\displaystyle \large{\begin{cases} x-y=1 \\ x+3y=9 \end{cases}}[/tex]

Solve by elimination of x-terms by multiplying either one of equations with -1:

For this, I choose to multiply -1 in first equation:

[tex]\displaystyle \large{\begin{cases} -1(x-y=1) \\ x+3y=9 \end{cases}}\\\displaystyle \large{\begin{cases} -x+y=-1 \\ x+3y=9 \end{cases}}[/tex]

Then add both equations:

[tex]\displaystyle \large{-x+x+y+3y=-1+9}\\\displaystyle \large{4y=8}[/tex]

Divide both sides:

[tex]\displaystyle \large{\dfrac{4y}{4} = \dfrac{8}{4}}\\\displaystyle \large{y=2}[/tex]

Next, substitute y = 2 in one of equations to solve for x:

For this, I choose to substitute y = 2 in the first equation:

[tex]\displaystyle \large{x-y=1}[/tex]

Substitute y = 2 in:

[tex]\displaystyle \large{x-2=1}[/tex]

Add both sides by 2:

[tex]\displaystyle \large{x-2+2=1+2}\\\displaystyle \large{x=3}[/tex]

Hence, the solution is x = 3 and y = 2 or you can write as in coordinate form (3,2)

__________________________________________________________

First method is elimination method, I’ll demonstrate another method which is by using matrices to find the solutions.

Given:

[tex]\displaystyle \large{\begin{cases} x-y=1 \\ x+3y=9 \end{cases}}[/tex]

Write the system of equations in matrices form:

[tex]\displaystyle \large{\left[\begin{array}{ccc}1&-1\\1&3\end{array}\right] \left[\begin{array}{ccc}x\\y\end{array}\right] =\left[\begin{array}{ccc}1\\9\end{array}\right]}[/tex]

Let:

[tex]\displaystyle \large{A=\left[\begin{array}{ccc}1&-1\\1&3\end{array}\right] }\\\displaystyle \large{X=\left[\begin{array}{ccc}x\\y\end{array}\right] \\\displaystyle \large{B = \left[\begin{array}{ccc}1\\9\end{array}\right] }[/tex]

From [tex]\displaystyle \large{AX=B \to X=A^{-1}B}[/tex] where:

[tex]\displaystyle \large{A^{-1}=\dfrac{1}{\det A} \left[\begin{array}{ccc}d&-b\\-c&a\end{array}\right] = \dfrac{1}{ad-bc} \left[\begin{array}{ccc}d&-b\\-c&a\end{array}\right] }[/tex]

Find [tex]\displaystyle \large{\det A}[/tex]:

[tex]\displaystyle \large{\det A = ad-bc = 3+1=4}[/tex]

Therefore:

[tex]\displaystyle \large{A^{-1} = \dfrac{1}{4}\left[\begin{array}{ccc}3&1\\-1&1\end{array}\right]}\\\therefore \displaystyle \large{X = \dfrac{1}{4}\left[\begin{array}{ccc}3&1\\-1&1\end{array}\right] \left[\begin{array}{ccc}1\\9\end{array}\right]}[/tex]

Evaluate the matrices:

[tex]\displaystyle \large{X= \dfrac{1}{4}\left[\begin{array}{ccc}3(1)+1(9)\\-1(1)+1(9)\end{array}\right] }\\\displaystyle \large{X= \dfrac{1}{4}\left[\begin{array}{ccc}3+9\\-1+9\end{array}\right] }\\\displaystyle \large{X= \dfrac{1}{4}\left[\begin{array}{ccc}12\\8\end{array}\right]}\\\displaystyle \large{X= \left[\begin{array}{ccc}3\\2\end{array}\right] }\\\therefore \displaystyle \large{\left[\begin{array}{ccc}x\\y\end{array}\right] = \left[\begin{array}{ccc}3\\2\end{array}\right]}[/tex]

Therefore, the solution is x = 3 and y = 2


Related Questions

For the diagram at right, write and solve an equation to find x

Answers

Answer:

x = 24

Step-by-step explanation:

The formula for determining the sum of interior angles is:

[tex](n-2) * 180[/tex]

[tex]4 * 180 = 720[/tex]

Therefore to determine an equation for x, we must add up all the interior angle equations and set them equal to 720.

[tex](2x+3) +(3x+12) + (7x+14) + (9x+2) + (4x+8) + (3x+9) = 720\\28x + 48 = 720\\28x = 672\\x = 24[/tex]

The equation and answer above shows how to find x, which equals 24.

What is the value of x^2+y^2 given the following system?
x+y=10
x-y=8

Answers

Answer:

I hope this helps, you can ask any questions for clarification

What scientific value for n will make this equation true? (4.8 × 10–3)(n) = 9.6 × 109 2.0 × 10–6 2.0 × 10–3 2.0 × 103 2.0 × 1012

Answers

The scientific value for n that will make the equation (4.8 × 10^(-3))(n) = 9.6 × 10^9 true is given by: Option D: 2.0 × 10^(12)

How does scientific notations work?

The number is written in the form  [tex]a \times 10^b[/tex]  where we have [tex]1 \leq a < 10[/tex]

The number b shows the order, which is the most important figure for which scientific notation is used. It tells us how much order large or small a value is in powers of 10. We can for a time, ignore the value of 'a' for two comparable quantities and only compare their orders(this type of comparison is useful when difference is too big, like size of human to size of a star etc sort of comparisons).

Scientific notations have some of the profits as:

Better readability due to compact representation

Its value in terms of power of 10 is known, which helps in easy comparison of quantities differing by a large value.

Finding the value of n from the given equation:

[tex](4.5 \times 10^{-3}) \times n = 9.6 \times 10^9\\\\\text{Dividing both the sides by } (4.5 \times 10^{-3}) \\\\n = \dfrac{9.6 \times 10^9}{4.5 \times 10^{-3}} = \dfrac{9.6}{4.5} \times \dfrac{10^{9}}{10^{-3}}\\\\n \approx 2.1333 \times 10^{9-(-3)} = 2.1333 \times 10^{12} \approx 2.0 \times 10^{12}[/tex]

Thus, the scientific value for n that will make the equation (4.8 × 10–3)(n) = 9.6 × 10^9 true is given by: Option D: [tex]2.0 \times 10^{12}[/tex]

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Answer: D

Step-by-step explanation:

Paul is making grey paint. He mixes black and white paint in the ratio 1:3. He makes 35 litres of grey paint. How much white paint does he use?

Answers

1 part black, four parts white. 35/4 = 8.75. There are 3 parts so 8.75* = 26.25 liters of white paint

What is the domain and range of the following graph

Answers

Answer:

Step-by-step explanation:

Domain is x-values the graph can have

  x = [-3,22]

range is the y values the graph includes

   range-=  [-3,+2]

2. A traffic study was conducted on a busy street. In 15-minute intervals from 6:30 a.m. to 8:00
a.m., the number of vehicles that passed a certain point in one minute was recorded in the table
below. Write an equation for the curve of best fit, then approximate the number of cars that passed
the point at 9:15 a.m.

Answers

The line of best fit of the traffic study is a line through a scatterplot of data points which shows the relationship between the points.

How to illustrate the equation?

Your information is incomplete as the table isn't given. Therefore, an overview will be given.

The least square methods is used by statisticians to arrive at the geometric equation for the line. A straight line will simply result from a simple regression of two or more independent variables.

A regression that has to do with multiple related variables lead to a curved line. The line of best fit is an important output of regression analysis.

A regression that has two independent variables will have a formula with:

y = c + b1x1 + b2x2

where,

c = constant

b1 = first regression coefficient

x1 = first independent variable

b2 = second regression coefficient

x2 = second independent variable.

In conclusion, the line of best fit expresses the relationship in a scatterplot of the data points.

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what is the constant of proportionality of the below

Answers

Answer:

Proportionality constant k

When two variables are directly or indirectly proportional to each other, then their relationship can be described as y = kx or y = k/x, where k determines how the two variables are related to one another. This k is known as the constant of proportionality.

Answer: Proportionality constant k

Step-by-step explanation:

below?

I need help on this one

Answers

I think it’s A. Because of the fact that it’s not at one full pound yet and the rest are too far away to be true

X/3+7=12
Help :)
I need to write more to send it so…

Answers

Answer:

15

Step-by-step explanation:

To solve you have to get x by itself on one side.

x/3+7=12

First, you move the seven over.

x/3+7-7=12-7

Simplify.

x/3=5

Now to get x by itself you can multiply both sides by 3.

x/3*3=5*3

Simplify.

x=15

Answer:

x = 15

Step-by-step explanation:

x/3 + 3⋅7/3 = 12

x+3⋅7/3=12

x+21/3

X=15

A closet is in the shape of a rectangular prism. It is 214feet long, 3 feet wide, and 4 feet tall.

What is the volume of the closet?

Answers

Putting each of these lengths into the volume equation (length×width×height)…
214×3×4=2568
Therefore the volume is: 2568ft³

7
f(x) = 3x2 + 4x – 7
g(x) = 2x – 11

Answers

Answer:

g[f(x)] = 6x² + 8x - 25

Step-by-step explanation:

g[f(x)] = g(3x² + 4x - 7)

= 2(3x² + 4x - 7) - 11

= 6x² + 8x - 14 - 11

= 6x² + 8x - 25

the volume inside a rectangular storage room is 2,025 cubic feet. the room is 9 feet high. find the the area of the floor.

Answers

Answer:

(Sorry if this answer is not correct, if it is or is not, please tell me in the comments!)

232.777778 feet squared (feel free to round the answer)

Step-by-step explanation:

The formula on how to find the volume is:

(the area of the floor) x (the height of the room) = 2025 cubic feet

We already know the height, so we need to plug it in.

(the area of the floor) x 9 feet = 2095 cubic feet

To get the area of the floor, we need to divide 2095 by 9.

So, the area of the floor is exactly 232.777778 feet squared.

Answer:

225 ft²

Step-by-step explanation:

Formula

Volume = Base Area x HeightVolume = 2,025 ft³Height = 9 ft

Solving :

Base Area = Volume / HeightBase Area = 2,025 / 9Base Area = 225 ft²

the phases in algebra are

Answers

Answer:

rhetorical stage, syncopated stage, symbolic stage

Step-by-step explanation:

28x+1=32x-1 solve for x

Answers

Answer:

x = 1/2

Step-by-step explanation:

28x + 1 = 32x - 1 <== subtract 28x from both sides

-28x      -28x

1 = 4x - 1 <== add 1 to both sides

+ 1      + 1

2 = 4x <== divide both sides by 4 to isolate the variable

/4   /4

1/2 = x

Hope this helps!

Answer:

[tex] \Large{\boxed{\sf x = \dfrac{1}{2} }} [/tex]

[tex] \\ [/tex]

Explanation:

Given equation:

[tex] \sf 28x + 1 = 32x - 1 [/tex]

[tex] \\ [/tex]

Subtract 28x from each side :

[tex] \sf 28x + 1 - 28x = 32x - 1 - 28x \\ \\ \sf 1 = 4x - 1 [/tex]

[tex] \\ [/tex]

Add 1 to both sides:

[tex] \sf 1 + 1 = 4x \\ \\ \sf 2 = 4x [/tex]

[tex] \\ [/tex]

Divide both sides by 4:

[tex] \sf \dfrac{2}{4} = \dfrac{4x}{4} \\ \\ \\ \boxed{\boxed{\sf x = \dfrac{1}{2} }} [/tex]

[tex] \\ \\ [/tex]

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A pet store has 4 tanks of fish. Each tank has 32 fish. How many fish does the store have?

Answers

Answer:

128

Step-by-step explanation:

32 × 4 = 128

Each tank has 32, and there are four, so 32 times 4.

The store has 128 fish in the tank.

What is the fundamental principle of multiplication?

Multiplication is the mathematical operation that is used to determine the product of two or more numbers. If an event can occur in m different ways and if following it, a second event can occur in n different ways, then the two events in succession can occur in m × n different ways.

We are given that pet store has 4 tanks of fish. Each tank has 32 fish.

Therefore,

Total fish =  Number of fish that a tank can hold x Number of tanks

32 × 4 = 128

Hence, we get 32 for each tank, and there are four,

Thus, 32 times 4.

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How long does this lease last?

Answers

Im not sure what the question is. What lease?

Is it possible to rewrite any proof that uses the AAS Congruence Theorem as a proof that uses the ASA Congruence Theorem? Explain your reasoning.

Answers

Answer: Yes

Step-by-step explanation:

If you were to use AAS, you could prove the third pair of angles congruent by using the fact that the sum of the measures of the angles of a triangle is 180 degrees, and since you have two of the angles, you can solve for the third pair of angles, which would be congruent.

The following function represents the production cost f(x), in dollars, for x number of units produced by company 1:

f(x) = 0.15x2 − 6x + 400

The following table represents the production cost g(x), in dollars, for x number of units produced by company 2:

Answers

The function of the production cost is a quadratic function, and the maximum production cost of the company is $340

How to determine the maximum production cost of the company?

The function of the production cost is given as:

f(x) = 0.15x² - 6x + 400

Differentiate the function

f'(x) = 0.3x - 6

Set the function to 0

0.3x - 6 = 0

Add 6 to both sides

0.3x = 6

Divide both sides by 0.3

x = 20

Substitute x = 20 in f(x) = 0.15x² - 6x + 400

f(20) = 0.15 * 20² - 6 *20 + 400

Evaluate

f(20) = 340

Hence, the maximum production cost of the company is $340

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Please help The diagram below shows a square prism. The plane ABC is inside the
prism, and M is the midpoint of the base diagonal BC. MD. = square root 18
b Hence find, correct to the nearest degree, the angle that the plane ABC
makes with the base of the prism. Diagram is attached below.

Answers

Answer:

  43°

Step-by-step explanation:

Triangle ADM is a right triangle with legs AD=4 cm and DM=√18 cm. The angle at M is the angle of interest. It can be found using the inverse tangent function.

  Tan = Opposite/Adjacent

  tan(∠AMD) = AD/MD = 4/√18

  ∠AMD = arctan(4/√18) ≈ 43.31°

The angle the plane makes is about 43°.

Answer:

the measure of the angle that the plane ABC makes with the base of the prism = 43 degree (to the nearest degree)

Step-by-step explanation:

We notice that the plane ABC and the base of the prism intersect along the line BC

And as the plane (ADM) is perpendicular to the line BC

then the angle between the plane ABC and the base of the prism is the angle AMD

Let θ be the measure of the angle AMD

[tex]\begin{aligned}\tan (\theta) &=\frac{A D}{M D} \\&=\frac{4}{\sqrt{18}}\end{aligned}[/tex]

[tex]\begin{aligned}\Rightarrow \theta &=\tan ^{-1}\left(\frac{4}{\sqrt{18}}\right) \\&=43,31385 \ldots\end{aligned}[/tex]

Jacob spent $34 on a magazine and seven notepads. if the magazine cost $6, then how much was each notepad?

Answers

Step-by-step explanation:

first you subtract 34 and 6 to get 28

now its 7 multiplyed by some number

each notepad 4 dollars cause 7x4=28

Answer:4 dollars

PLEASE HELP! PLEASE HELP! I NEED TO GET THIS RIGHT! PLEASE ANSWER FULLY!

Answers

Answer:

what do you need help with

y=4x+3 system of equations

Answers

Step-by-step explanation:

y=4x + 3

it should have another one

HELP PLEASE URGENT, ASAP. GRADE 11 TRIGONOMETRY MATH, ill give brainliest.

Answers

Answer:

deedww

Step-by-step explanation:

Which property of addition is shown below?

If x = a + bi and y = –a – bi, x + y = 0.
commutative property
identity property
associative property
inverse property

Answers

inverse property is being shown

Answer: D

Step-by-step explanation:

Solve for x and y
7y - 5x = 45
x = 8 – 2y

Answers

Answer:

Hope the pictures will help you.

The solution to the system of equations is x = -2 and y = 5.

What is the solution to the system of equations?

Given the parameters:

7y - 5x = 45

x = 8 - 2y

To solve the system of equations, substitute the expression for x from the second equation into the first equation.

7y - 5x = 45

Plug in x = 8 - 2y:

7y - 5( 8 - 2y) = 45

7y - 40 + 10y = 45

Collect and add like terms:

7y + 10y = 45 + 40

17y = 85

y = 85/17

y = 5

Plug the value of y into the second equation and solve for x:

x = 8 - 2y

Plug in y = 5:

x = 8 - 2( 5 )

x = 8 - 10

x = -2

Therefore, the value of x is -2 and y is 5.

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I got these three exercises that I gotta do and I need help. It’s in Hebrew but it would mean a lot if someone could help!

Answers

Answer:

i dont lnow the language sorry

Radius ob measures x units. which expression represents the circumference of the smaller circle with radius oa? (startfraction pi over 3 endfraction)x units (startfraction 2 pi over 3 endfraction)x units 2πx units 6πx units

Answers

The circumference of the smaller circle is C =  2*pi*x/3.

We have given that radius ob measures x units

What is the formula for the circumference of the circle ?

circumference of the circle is given by,

[tex]C = 2\times \pi \times R[/tex]

where pi = 3.14

R= radius

we have two circles, A and B, where B is the larger circle and A is the smaller circle.

We know that,The circumference of B is 3 times the circumference of A.

The radius of circle B is OB = x

The radius of circle A is OA

We want to find an expression of OA.

The circumference of circle B is given by

[tex]C(B) = 2\times \piOB = 2\times pi\times x[/tex]

The circumference of circle A  is given by

[tex]C(A) = 2\times\pi\times OA[/tex]

we know that the circumference of circle B is 3 times the circumference of circle A,

[tex]C(B) = 3\times C(A)[/tex]

replacing the equations for the circumferences

[tex]2\times\pi\times x = 3\times (2\times pi\times OA)[/tex]

We have divide both sides by [tex]2\pi[/tex]we get:

[tex]x = 3\times OA[/tex]

Now we want to solve this for OA, then we need to isolate it,

[tex]x/3 = OA[/tex]

We can conclude that the radius of the smaller circle is equal to x/3.

Then the circumference of circle A is

[tex]C(A) = 2\times pi\times x/3[/tex]

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Answer:

c

Step-by-step explanation:

Josh studied for his
science test from
3:45 p.m. until
5:30 p.m each day for
three days. how long
did he study in all?

Answers

he studied for 495 minutes. 165 minutes a day.

Answer: He studied for 315 minutes. Because he studied for 1hr and 45 mins (105 mins). Then you multiply this by 3 because it's been three days.

Hope this helps!

17=3x-4
Find the value of x​

Answers

Answer:

x=7

Step-by-step explanation:

Noah is making grilled cheese sandwiches for friends. He has 24 ounces of cheese. He plans to split the cheese evenly between 6 sandwiches.

Write an equation to determine how many ounces of cheese, ccc, Noah can use on each sandwich.

Answers

Answer:

24 / 6 = ccc

Step-by-step explanation:

There is 24 oz of cheese total that will be split evenly (divided) into 6 parts.

Each part will equal one sandwich worth of cheese (ccc) on the other side of the equation.

This one is very simple to solve, you could just calculate 24/6 to get your answer. But I'll go through it using typical algebra you would use for a less simple equation.

To solve:

Multiply by 6 to cancel the division by 6 on the left side

24 = 6ccc

Divide by 6 to isolate ccc again

4 = ccc

So each sandwich would get 4oz of cheese.

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