Given the equation log2x + log2(x – 7) = 3, solve for x.

Answers

Answer 1

Answer:

         x∈{-1, 8}

Step-by-step explanation:

[tex]\log_2x +\log_2(x-7) = 3\\\\\log_2[x\cdot(x-7)]= 3\log_22\\\\\log_2(x^2-7x)= \log_22^3\\\\x^2-7x=2^3\\\\x^2-7x-8=0\quad\implies \quad a=1\,,\ \ b=-7\,,\ \ c=-8 \\\\x=\dfrac{-(-7)\pm\sqrt{(-7)^2-4\cdot1\cdot(-8)}}{2\cdot1}= \dfrac{7\pm\sqrt{49+32}}{2} =\dfrac{7\pm\sqrt{81}}{2}\\\\x=\dfrac{7+9}2=8\qquad\vee\qquad x=\dfrac{7-9}2=-1[/tex]


Related Questions

When does the expression below equal
10?
n + 3
A when n=4
B when n = 10
C when n = 13
D when n = 7

Answers

Answer: n(7)+3=10
Explanation: 7+3 equals 10

[tex]▪▪▪▪▪▪▪▪▪▪▪▪▪  {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪[/tex]

When n = 7

[tex]n + 3[/tex]

[tex]7 + 3[/tex]

[tex]10[/tex]

hence, the given expression is equal to 10, when n = 7

A visual-effects model maker for a movie draws a spaceship using a ratio of 1 : 24. The drawing of the spaceship is 22 inches long. What is the length of the spaceship in the movie?
Group of answer choices

Answers

Answer:

Length of spaceship in movie = 528

Step-by-step explanation:

Given that:

Drawing ratio of spaceship = 1 : 24

It means that 1 inch on drawing equals 24 inches in movie

Drawing of spaceship = 22 inches

Length of spaceship in movie = x

As the relationship is proportional,

1 : 24 :: 22 : x

Product of mean = Product of extreme

24*22 = x

x = 528

Hence,

Length of spaceship in movie = 528

True or False To find the circumference of a circle you multiply the diameter by pi

Answers

Answer:

false

Step-by-step explanation:

Formula: c=2[tex]\pi[/tex]r

Circumference= two times pi times radius

Solve the area formula for a circle, A = πr2, for r2.






r2 = Aπ

r2 = A – π

Answers

Answer:

The solution of r² is r² = [tex]\frac{A}{\pi }[/tex]

Step-by-step explanation:

To solve an equation for one of its variables, do that

Separate the term of this variable on one side and the other terms on the other sidesMake the coefficient of the variable equals1 (if it is not 1)

Let us solve the question

∵ The formula of the area of the circle is A = π r²

∵ The subject is r² ⇒ The variable which we need to solve for it

→ By using the 1st step up divide both sides by π to move it from the right

   side to the left side

∵ [tex]\frac{A}{\pi }[/tex] = [tex]\frac{\pi r^{2}}{\pi }[/tex]

∴ [tex]\frac{A}{\pi }[/tex] = r²

→ Switch the two sides

r² = [tex]\frac{A}{\pi }[/tex]


The geometric figure that is created after plotting the points A (-3,-6), B (5,-6), C (5,-4) and D (-3,-4) on the
coordinate plane is a
A triangle.
B square.
c circle.
D rectangle.

Answers

Answer:

D. a rectangle

Step-by-step explanation:

On a coordinate plane it is D. RECTANGLE (I think)

Can anyone help mee!!!

Answers

Answer: I want to say 30 degrees you have to put the degree simble

Step-by-step explanation:

Answer: 30 degrees
Explanation: all of the angles added together in a triangle is equivalent to 180 degrees
180-130-20=30

30 points! Will mark brainliest. No random answer please.

Answers

Answer:

to determine whether the equation of the line parallel or perpendicular.we have to find there slope.

Step-by-step explanation:

2x+3y=15

3y=15-2x

y=15/3 -2x/3

y=5-2x/3

y=-2x/3 +5

so the cooficient tell us the slope of the line so it is -2/3

4x+6y=-48

6y=-48-4x

y=-4x/6 -48/6

y=-4x/6 -8

so the slope of this line is -4/6

now to say two lines are parallel there slope should be the same

-2/3 ≠ -4/6

to say two line are perpendicular with one another the product of there slope should be -1

-2/3 * -4/6

=8/18

=4/9 which is different from -1

they are neither parallel nor perpendicular.

pls help me with this question i’ll be giving a brainliest to the person with the correct answer

Answers

Answer:

i believe it’s the second and third one, not too sure about the first

Step-by-step explanation:

~Hi ~ me ~ again ~ sorry ~ can ~ you ~ please ~ help ~ me ~ out ~ once ~ more?~

Answers

Answer:

b 19

Step-by-step explanation:

Answer:

the answer is 19, B.

Step-by-step explanation:

this is my first time answering a question. i hope this helps you.

which is a prime number 18 15 19 or 22

Answers

Answer:

19

Step-by-step explanation:

the only way u can get 19 is if you multiply 19x1 but other than that you cant get the number

the other numbers have more than one multiple but 19 only has one multiple

Answer:

19

Step-by-step explanation:

the only factors multiplyed that can make 19 is 1 and 19

15:1, 3, 5, 15

18:1, 2, 3, 6, 9, 18

22:1, 2, 11, 22

19:1, 19

take care

1) A tv has a sale price of $450 and has a sales tax of 6% Find the total price.
Sales tax:
Total price:

Answers

Answer:

Sales tax : $27

Total price : $477

Step-by-step explanation:

Given that:

Sale price of tv = $450

Sales tax = 6%

Amount of sales tax = [tex]\frac{6}{100}*450[/tex]

Amount of sales tax = 0.06 * 450

Amount of sales tax = $27

Total price = Sale price + Sales tax

Total price = 450 + 27 = $477

Hence,

Sales tax : $27

Total price : $477

4/3(6y+21)-17>43 help pls

Answers

Answer:

Step-by-step explanation:

4/3(6y+21)-17=43

move all terms to the left:

4/3(6y+21)-17-(43)=0

Domain of the equation: 3(6y+21)!=0

y∈R

We add all the numbers together, and all the variables

4/3(6y+21)-60=0

You multiply all the terms by the denominator

-60*3(6y+21)+4=0

multiply elements

4.5m is__% of 90cm. And 90cm is ___% of 4.5m.

Pls help me! This is really hard.

Answers

You got this. Just a proportional issue once units of cm and m is converted.

1 meter is 100 centimeters (deci is 10, centi is 100, milli is 1000)

4.5 meter = 4.5 x 100 or 450 centimeters

(450/90)x100= 500%. 4.5 meters is 5 times longer than 90 cm
Cross check: 5x90=450

(90/450)x100= 20%
Cross check: .2x450=90

This has been answered before on Brainly

4.5m is 500% of 90cm

90cm is 20% of 4.5m.

Which statement describes a property of water?
O A. It is less dense as a solid than as a gas.
o B. It is less dense as a solid than as a liquid.
C. It is more dense as a gas than as a liquid.
0
D. It is more dense as a solid than as a liquid.

Answers

Answer:

the answer is D. dense means heavier, basically

Answer:

its D dense

Step-by-step explanation:

because dense means more inside

To the nearest unit, what is the perimeter of this pentagon?
27 units
29 units
30 units
34 units

Answers

I think it might be 27 no sure

Answer:

D(34)

Step-by-step explanation:

i did the math

Please help this is a major gradeeeeee

Answers

Answer:

45

Step-by-step explanation:

I think it’s
45 hopefully it’s right let me know!

Which gives the prices in order, from least to greatest

Answers

Answer:

is there a picture to go with the problem?

a student buys (x) fashion magazines and (y) sports magazines. Each fashion magazine costs $2.00 and each sports magazine costs $1.60. If the student buys a total of 8 magazines for $14.00, which equation best represents the situtation

Answers

Answer:

Step-by-step explanation:

the student buys a total of 8 magazines for $14.00

x+y = 8

x = 8-y

2x+1.6y = 14

2(8-y)+1.6y = 14

16-2y+1.6y = 14

16-0.4y = 14

0.4y =16-14 = 2

y = 2/0.4 = 5

x = 8-y = 3

The correct equation best represents the situation is,

⇒ x + y = 8

And, 2x + 1.60y = 14.00

What is an expression?

Mathematical expression is defined as the collection of the numbers variables and functions by using operations like addition, subtraction, multiplication, and division.

Given that;

A student buys (x) fashion magazines and (y) sports magazines.

And, Each fashion magazine costs $2.00 and each sports magazine costs $1.60.

Here, The student buys a total of 8 magazines for $14.00.

Hence, We can formulate;

⇒ x + y = 8

And, 2x + 1.60y = 14.00

Thus, The correct equation best represents the situation is,

⇒ x + y = 8

And, 2x + 1.60y = 14.00

Learn more about the mathematical expression visit:

brainly.com/question/1859113

#SPJ3

can someone please please please help me asap?!

Answers

Answer:

-1.5

Step-by-step explanation:

Rise is 3, run is -2

I hope this helps..

The non-fiction section of the Montgomery County Library has 15 racks. If each rack holds 528 books, what is the total collection of non-fiction books in the library.

Answers

Answer:

when you do 15×528 you get 7920 books

The total cost (c) in dollars of renting a car for n days is given by the inequality LaTeX: c\ge125+50nc ≥ 125 + 50 n. What is the maximum number of days for which a car could be rented if the total cost was $425?

Answers

Answer:

6 days

Step-by-step explanation:

Given the inequality expression of the total cost (c) in dollars of renting a car for n days as c ≥ 125 + 50n

To get the maximum number of days for which a car could be rented if the total cost was $425, substitute c = 425 into the expression and find n

425 ≥ 125 + 50n

Subtract 125 from both sides

425 - 125 ≥ 125 + 50n  - 125

300≥ 50n

Divide both sides by 50

300/50≥50n/50

6 ≥n

Rearrange

n≤6

Hence the maximum number of days for which a car could be rented if the total cost was $425 is 6days

Hola chicos, solo necesito ayuda con la vida. Solo bromeaba o lo estoy?

Answers

Answer:

no sé eres tú

Step-by-step explanation:

A triangle has an angle that measures 68°. Which of these can be the measures of the other two angles?

Answers

Answer:

56 degrees

Step-by-step explanation:

180-68=112

112/2=56

hope i could help!

Answer:

112

Step-by-step explanation:

The sum of the other two angles is 112 degrees (180-68 = 112).

But the question is, what triangle is it?

Two other angles could be:

1) 90 and 22 degrees;

2) two equal angles of 56 degrees

3) any that would satisfy the condition in the amount of 112 degrees.

help will mark brainliest plz plz plz

Answers

hope it will help you..............

Answer:

4.3

Step-by-step explanation:

subtract CD from CZ to find DZ

this is the same thing as CZ - CD = DZ

substitute in our values: 6.7 - 2.4 = DZ

you get DZ = 4.3

Is this congruent or not congruent? And is this
SSS
SAS
SSA
AAS
ASA
HL
PLEASE HELP, I will brainliest u

Answers

It's congruent by AAS

Answer: Answer is SSS ok

. A girl pushes herself up a steep ramp in her
wheelchair. She gains a vertical distance of
25.8 m when she reaches the top of the ramp.
She turns around and coasts back down the ramp.
If the combined mass of the girl and her wheelchair
is 64.6 kg, what would be her coasting speed at the
bottom of the ramp? Show all your work.

Answers

Answer:

32 Joule by 21 secs

Step-by-step explanation:

I hope that's the correct answer. Best of luck

If point A(-8, 5) is reflected over the line y=2 and then translated according to the rule (x,y) -> (x-1, y-4), what quadrant will point A be in?

Answers

9514 1404 393

Answer:

  3rd quadrant

Step-by-step explanation:

The second-quadrant point will lie in the 3rd quadrant after reflection over the line. Its coordinates there will be ...

  A'(-8, 2·2 -5) = A'(-8, -1)

Then, translation down and to the left will move it further into the 3rd quadrant, to ...

  A''(-8-1, -1-4) = A''(-9, -5) . . . . a 3rd-quadrant point

hii can someone help with this pls :)
i think it’s (0.6,2.8) but i’m not sure so can someone confirm

Answers

Answer:

[tex]R(x,y) = (0.8,-1.2)[/tex]

Step-by-step explanation:

The coordinates of QS are:

[tex]Q(x_1,y_1) = (-2,-6)[/tex]

[tex]S(x_2,y_2) = (5,6)[/tex]

The ratio is represented as:

[tex]R_{m:n} = 2:3[/tex]

Required

Find the coordinates of R

The coordinates of R is calculated by:

[tex]R(x,y) = (\frac{mx_2 + nx_1}{m+n},\frac{my_2 + ny_1}{m+n})[/tex]

Substitute values for m, n, x's and y's

[tex]R(x,y) = (\frac{2 * 5 + 3 * -2}{2+3},\frac{2*6 + 3*-6}{2+3})[/tex]

[tex]R(x,y) = (\frac{4}{5},\frac{-6}{5})[/tex]

[tex]R(x,y) = (0.8,-1.2)[/tex]

None of the options is correct

Decrease £313 by 62%
Give your answer rounded to 2 DP.

Answers

Answer:

194.06

Step-by-step explanation:

£313 decreased by 62% is £118.94

In order to determine the answer, the first step to take is to determine the value of 62% of £313.

Value of 62% = 62% x £313

0.62 x £313 = £194.06

The second step is to subtract the value of 62% of £313 from £313

£313 - £194.06 = £118.94

In order to decrease £313 by 62%, the first step is to determine the value of 62% of £313 and then subtract the value gotten from the previous step from £313.

A similar answer was solved here: https://brainly.com/question/18837466?referrer=searchResults

14. Max wants to buy some shorts that are
priced at $8 each. He decided to buy a pair
of sneakers for $39, but the total cost of the
shorts and the sneakers must be less than $75.
a. Write an inequality to find out how many
pairs of shorts Max can buy.
b. Suppose that Max wants to buy 6 pairs
of shorts. Will he have enough money?
Explain.
c. Solve the inequality to find the greatest
number of pairs of shorts that Max can buy.
Show your work.

Answers

Answer:

A. ($39)+(8)+(8)+(8)+(8)=71

Therfore he can buy 4 pairs of shorts.

B. No, if he wanted to buy 6 pairs of shorts it would be $87.00 with the sneakers. If he wanted to buy the shorts by themselves then it would only be $48.00 WITHOUT the sneakers.

C. The most amount of shorts he can buy would be 4 WITH the sneakers.

Step-by-step explanation:

Hope this helps. Not sure if right or not but when i was typing it out it made sense. Goodluck! brainliest?

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