Question

PLEASE HELP!!
What number must you add to complete the square?
x^2+8x=15

a.32
b. 4
c. 16
d. 8

Answer 1

first subtract 15 from both sides
x^2+8x-15=0

Answer 2

you can factor that!

Answer 3

is it d??

Answer 4

so any brain storming here

Answer 5

oh my bad sorry i did not read the question clearly

Answer 6

forgot my proposal

Answer 7

you need to complete the square

Answer 8

focus on left hand side x^2+8x
what can you add to make that a perfect square

Answer 9

x^2+2(4x)+ ....

Answer 10

you did say the answer before

Answer 11

Complete the square:

x^2+8x=15
Take HALF of the coefficient of 8x. Your response?

Answer 12

sorry i confused you :) my bad

Answer 13

4

Answer 14

Now square it.

Answer 15

4*4=16

Answer 16

Good. Now write +16 on both sides of your equation. Share your work, please.

Answer 17

Write the whole equation, including the +16 on the left side and another +16 on the right side.

Answer 18

x^2+8x+16=15+16

Answer 19

Very nice. Note that your x^2 + 8x + 16 is a perfect square.

Can you write it as the square of a binomial? ( ? + ? ) ^2

Answer 20

(x +4)^2 is this right??

Answer 21

correct
what is 15 + 16? that goes on the right side

Answer 22

\(x^2+8x+\color{red}{16}=15+16\)

What did you add to complete the square?

Answer 23

x^2+ 8x +16 =31

Answer 24

@mathstudent55 @mathmale

Answer 25

(x +4)^2 is this right?? yes, it is correct.

Thus, you have (x+4)^2=31

Take the square root of both sides, being certain to include the plus-or-minus sign in front of your Sqrt(31).,

Your result?

Now solve this result for x. You MUST end up with two different roots.

Answer 26

\[x^2+2.4.x=15\]here all u r missing is \(4^2\)therefore add \(4^2\) both the sides\[x^2+2.4.x+4^2=15+16\]\[(x+4)^2=31\]

Answer 27

Take 8, divide it by 2, and square the result. The answer is 16. You need to add 16 to both sides to complete the square.