Calculate the value of k for which the polynomial equation f(x)=x^3-kx+12 has the root of x=-4

Answers

Answer 1

If x = -4 is a root of f(x), then dividing f(x) by x + 4 leaves a remainder of 0.

Compute the quotient,

(x³ - kx + 12) / (x + 4)

x³ = x² • x, and

x² (x + 4) = x³ + 4x²

Subtract this from the dividend (f(x)) to get an initial remainder of

(x³ - kx + 12) - (x³ + 4x²) = -4x² - kx + 12

-4x² = -4x • x, and

-4x (x + 4) = -4x² - 16x

Subtract this from the previous remainder to get a new one of

(-4x² - kx + 12) - (-4x² - 16x) = (16 - k) x + 12

(16 - k) x = (16 - k) • x, and

(16 - k) (x + 4) = (16 - k) x + 64 - 4k

which gives the next remainder,

((16 - k) x + 12) - ((16 - k) x + 64 - 4k) = 4k - 52

4k - 52 does not divide x, so we're done and what we've shown is

f(x) / (x + 4) = x² - 4x + 16 - k + (4k - 52)/(x + 4)

(just gathering the bold terms above and the last remainder)

The remainder should be 0, so that

4k - 52 = 0

4k = 52

k = 13


Related Questions

Math please help 20 points plus brainly if you can answer each question.


The perimeter of a rectangle is 40 cm. The length is 14 cm.
Let x = width of the rectangle.

Ravi says he can find the width using the equation 2(x + 14) = 40.
Fran says she can find the width using the equation 2x + 28 = 40.

Answer the questions to solve the equations and to compare the steps and solutions.

1. Which of these is the most helpful first step for solving Ravi's equation, 2(x + 14) = 40?

Circle the best answer.

Add 14 to both sides
Subtract 14 from both sides
Divide both sides by 2
Multiply both sides by 2














2. What would your next step be?


Write your answer in the space below.















3. Solve Ravi's equation, 2(x + 14) = 40, to find the width of the rectangle. Show your work.


Write your answer in the space below.















4. Which of these is the most helpful first step for solving Fran's equation, 2x + 28 = 40?

Circle the best answer.

Multiply both sides by 2
Subtract 28 from both sides
Divide both sides by 2
Add 28 to both sides














5. What would your next step be?


Write your answer in the space below.















6. Solve Fran's equation, 2x + 28 = 40, to find the width of the rectangle. Show your work.


Write your answer in the space below.















7. The two equations have different solution steps. Do they have the same solution? Use the distributive property to show why this answer makes sense.


Write your answer in the space below.

Answers

Answer:

number 1 is D

number 2 is distribute 2 into x and 14(multiplying)  getting 2x+28=40

then subtract 28 from each side  40-28=12  after just simply divide 2x by its self and into 12 getting 6

number 3 is 12

number 4 is subtract 2 from both side

number 5 is divide

number 6 is 6

I hope this helps have a great day!

Step-by-step explanation:

3. Sam and Tim each have savings accounts. Every month they each put in some of their
earnings from mowing lawns. Use the tables to find the y-value of the solution to the
system shown.
х
1
2
3
4
f(x)
80
110
140
170
х
1
2
3
4
g(x)
100
120
140
160

Answers

Answer:

[tex]y = 30x +50[/tex] --- Sam

[tex]y = 20x +80[/tex] --- Tim

Step-by-step explanation:

Given

Sam                         Tim

х  --- f(x) ---------------  g(x)

1  --- 80   --------------- 100

2  --- 110  --------------- 120

3  --- 140 --------------- 140

4 --- 170 -------------- 160

Required

Determine the y value

y value implies the equation of the table

Calculating the equation of Sam

First, we need to take any corresponding values of x and y

[tex](x_1,y_1) = (1,80)[/tex]

[tex](x_2,y_2) = (4,170)[/tex]

Next, we calculate the slope (m)

[tex]m = \frac{y_2 - y_1}{x_2 - x_1}[/tex]

[tex]m = \frac{170 - 80}{4 - 1}[/tex]

[tex]m = \frac{90}{3}[/tex]

[tex]m = 30[/tex]

Next, we calculate the line equation using:

[tex]y - y_1=m(x-x_1)[/tex]

[tex]y - 80 = 30(x - 1)[/tex]

[tex]y - 80 = 30x - 30[/tex]

Make y the subject

[tex]y = 30x - 30 + 80[/tex]

[tex]y = 30x +50[/tex]

Calculating the equation of Tim

First, we need to take any corresponding values of x and y

[tex](x_1,y_1) = (1,100)[/tex]

[tex](x_2,y_2) = (4,160)[/tex]

Next, we calculate the slope (m)

[tex]m = \frac{y_2 - y_1}{x_2 - x_1}[/tex]

[tex]m = \frac{160 - 100}{4 - 1}[/tex]

[tex]m = \frac{60}{3}[/tex]

[tex]m = 20[/tex]

Next, we calculate the line equation using:

[tex]y - y_1=m(x-x_1)[/tex]

[tex]y - 100 = 20(x - 1)[/tex]

[tex]y - 100 = 20x - 20[/tex]

Make y the subject

[tex]y = 20x - 20+100[/tex]

[tex]y = 20x +80[/tex]

What is the recursive formula for this sequence? 12, 16, 20, 24, 28, ...​

Answers

Answer:

A

Step-by-step explanation:

first term is 12, and following terms are obtained adding 4 to previous term.

Carmen has taken out a loan for $800 to buy a car. She plans to pay back the loan at a rate of $40 per month. Ramona has borrowed $500 to buy a car, which she plans to pay back at a rate of $20 per month.

How long will it take Ramona to pay back her loan?​

Answers

25 months, hope this helps!

Answer:

It will take Ramona 25 months or 2 years and 1 month to pay back for the car.

Can someone please help with writing this out as equation?

The student council has decided to sell t-shirts with a school logo to promote school spirit. Amanda investigated 1 company that would charge $75 to make the printing screen for the shirts, and then $5.50 per shirt. Adam checked out a 2nd company that would charge a straight $7 per shirt. Which company's option would respresent a proprtional relationship? You should support your answer with an equation, a table of values, or a graph.

Answers

1+1=2 ;&;&:’snaj8:&;$/&/8182929857748382

Find the sum. Write your answer as a decimal.
-5.74 + 5.5 =

Answers

Answer:

-0.24

Step-by-step explanation:

Math is math i just know it in my head i do nt know how tpo explain it

Please help me with 4-6 ASAP I will give 30 points

Answers

Answer:

i did that paper made 100 but i was looking for it to help u and when i got it i tripped with my enchaladas im tryna clean it to get the answers

Step-by-step explanation:

Bob bought the 24 fish for $51.36. How much did each fish cost him? Show your calculation.

Answers

Answer:

2.14

Step-by-step explanation:

2.14x24=51.36

What is the simplified ratio of female to male students in a class, if there are 18 boys and 9 girls?

Answers

9:18 = 1:2
There are 1 to 2 females to males

GIVING BRAINLIST Use the number line to answer the question. Each tick represents 1 unit.








Which of the following points represents the largest number?


P

M

J

H

Answers

The answer is p , merry Christmas

I NEED HELP ASAP IT IS DUE TODAY!!,

Lori needs a length of twine 8.5 meters long to mark a row in her garden. Andrew needs a length of twine 7.28 meters long for his row. They have one length of twine that measures 16.29 meters.

After they each take the lengths they need, how much twine will be left?

Answers

Answer:

.51 meters of twine

Step-by-step explanation:

add the numbers of twine they each need which is 15.78 then subtract the 16.29 they have minus the 15.78 they need now you have a left over .51 meters

Which formula do we use to reflect over the y=x line
(x, y) → (y,x)
(x, y) → (-y, -x)
(x, y) = (-x, y)
(x, y) = (x, -y)

Answers

Answer:

the first one on the list because it said refect

a number, a variable, or a product of a number and one or more variables

Answers

Answer:

Polynomials

Step-by-step explanation:

i need help pls 1 - 8 thanks

Answers

Answer:

1. 0.5454

2. 8

3. 0.6785

4. 1.1428

5. 6

6. 1.5

7. 1.75

8. 1.6666

Step-by-step explanation:

calculator :)

Each ___ in a cell has its own specific function.

Answers

Answer:

organelle

Explanation: Mitochondria and the cell wall are both examples of organelles since they have their own specific functions (Mitochondria produces the energy and the cell wall protects the cell from things that might be a danger to the cell.

Each "organelle " in a cell has its own specific function.

What is organelles ?

Mitochondria and the cell wall are both examples of organelles since they have their own specific functions. Mitochondria produces the energy and the cell wall protects the cell from things that might be a danger to the cell.

A Cellular respiration is a component of a metabolic process which splits the glucose sugar molecule to produce energy in the form of ATP.

Since we know that Krebs' cycle, oxidative phosphorylation, and glycolysis are all components of cellular respiration.

The cellular respiration activities take place in the mitochondria of the cell, where the oxygen-rich environment which causes the sugar-like glucose to break down into an energy molecule.

A cell organelle having a membrane is a 'mitochondria'. It is a location for cellular respiration and metabolic activities which produce energy.

Learn more about mitochondria by using this link:

brainly.com/question/10688306

#SPJ6

$40 game; 30% off; 5% tax

Answers

Yo dude that’s cool where can I get it

The data was modeled with a linear best-fit function. What was the initial
purchase price?

X Y
4. 5,000
7. 6,875
9. 8,125
12. 10,000


A. $625
B. $2,500
C. $5,000
D. $5,625

Answers

Answer:

c

Step-by-step explanation:

Express each ratio as a unit rate. Round to the nearest tenth, if necessary.
100 miles in 2.5 hours
40 miles per hour
100
a. Yo
c.
25 miles per hour
1000
b. 250 miles per hour
d.
25
miles per hour
Please select the best answer from the choices provided
А
B
ОС
D

Answers

Answer:

c

Step-by-step explanation:

Answer:

A. 100 miles divide 2.5 hours = 40 miles per hour

Can someone help with this please?

Answers

Answer:

a) Function 1 has the greatest y-intercept

b) Only function 2 has a slope less than -2

c) Function 4 has the least steep slope

Answer:

1. Function 1

2. Function 2

3. Function 4

Step-by-step explanation:

y-intercept:   Function 1: 4, Function 2: 1, Function 3: -5, Function 4: -2

- Function 1 has the highest y-intercept

slope less than -2:  Function 1: 2, Function 2: -4, Function 3: 5, Function 4: -1

- Function 2 has a slope lower than -2

least steep graph: Function 1: steepness 2, Function 2: steepness 4, Function 3: steepness 5, Function 4: steepness 1

- Function 4 has the steepest graph

Sara has $180 to spend on a mixture of oranges and bananas. The oranges cost $3 per pound and the bananas cost $2 per pound. What equation can she use to graph a line showing the different amounts of oranges and bananas she can buy for $180?

Explain what does each elements of the equation represent.

pleasee guys i need help

Answers

Answer:

365

Step-by-step explanation:

2+3+180+180=

In which quadrant does the point S(-3, -4) lie?
quadrant I
quadrant II
quadrant III
quadrant IV

Answers

It would be quadrant III

Answer:

Quadrant 3

Step-by-step explanation:

Quadrant 3: (-, -)


A triangle has side lengths of 21, 27, and 35 inches. Is it
right triangle?

Answers

Answer: No
In right triangle we have 30:60:90
and the ratios are
x: x root of 3: 2x
so, for example, if we have side of length 3 against 30 degrees, then against 60 degrees the side will be 3 root of 3, and against 90 degrees it will be 6.
Hope it helps!

The sum of three numbers $x$ ,$y$, $z$ is 165. When the smallest number $x$ is multiplied by 7, the result is $n$. The value $n$ is obtained by subtracting 9 from the largest number $y$. This number $n$ also results by adding 9 to the third number $z$. What is the product of the three numbers?

Just take the $ out

Answers

You're given

x + y + z = 165

7x = n

n = y - 9

n = 9 + z

and you want to find xyz.

Solve the last three equations for x, y, and z :

7x = n   →   x = n/7

n = y - 9   →   y = n + 9

n = 9 + z   →   z = n - 9

Substitute x, y, and z into the first equation and solve for n :

n/7 + (n + 9) + (n - 9) = 165

n/7 + 2n = 165

n + 14n = 1155

15n = 1155

n = 77

Now solve for x, y, and z :

x = 77/7 = 11

y = 77 + 9 = 86

z = 77 - 9 = 68

Then the product is

xyz = 11 • 86 • 68 = 64,328

The product of the three numbers is 8,192,040. The sum of three numbers x, y, z is 165: x + y + z = 165

The problem states:

1. When the smallest number x is multiplied by 7, the result is n: 7x = n

2. The value n is obtained by subtracting 9 from the largest number y: n = y - 9

3. The value n is also obtained by adding 9 to the third number z: n = z + 9

Now, let's proceed to find the values of x, y, z, and n:

From equation (2), we can express x in terms of n:

x = n/7

Now, substitute the value of x in equation (1):

(n/7) + y + z = 165

From equation (3), we can express y in terms of n:

y = n + 9

Now, substitute the value of y in the equation above:

(n/7) + (n + 9) + z = 165

From equation (4), we can express z in terms of n:

z = n - 9

Now, substitute the value of z in the equation above:

(n/7) + (n + 9) + (n - 9) = 165

Combine the terms with n:

3n/7 = 165

To isolate n, multiply both sides by 7/3:

n = 165 * (7/3)

n = 385

Now, we have the value of n, which is 385. To find the values of x, y, and z, substitute n back into the respective equations:

x = n/7 = 385/7

≈ 55

y = n + 9 = 385 + 9

= 394

z = n - 9 = 385 - 9

= 376

Now, we have the values of x, y, z, and n:

x = 55,

y = 394,

z = 376,

n = 385

To find the product of the three numbers, simply multiply them:

Product = x * y * z

= 55 * 394 * 376

≈ 8,192,040

So, the product of the three numbers is 8,192,040.

To know more about three numbers:

https://brainly.com/question/30269736

#SPJ2

Each day Louders reads 30 pages

Answers

Answer:

woww

Step-by-step explanation:

PLS HELP PLS THE LAST QUESTION I ASKED PLSSSSS

Answers

Answer:

Okay nvm I have found it here is your graph I don't what type of graph you need so i will provide you with 2 of my choosings

Step-by-step explanation:

a size 8 kids shoe measures 9 2/3

Answers

What am I suppose to answer?

what number line shows the solution of -5x + 10 > -15

Answers

Answer: x<5

Step-by-step explanation: Subtract 10 from both sides. Simplify  -15-10 to  -25. Divide both sides by -5. Two negatives make a positive. Simplify 25/5 to 5.

Is 500% of 9 less than 10, greater than 10 but less than 100, or greater than 100?

Answers

What is that on your pfp


Identify the graph of the inequality 2(2x - 1) + 7 < 13 or -2x + 5 5–10.
-10
-5
0
5
10
+
5
O!
0
-10
5
10
-10
-5
0
5
10
DONE

Answers

Answer:

20

Step-by-step explanation:

good luck

I NEED HELP STAT

=12×0.75

Answers

Answer:

9

Step-by-step explanation:

use a calculator of just think about it

Answer:

9.00

Step-by-step explanation:

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