Question

What number must you add to complete the square? x^2 + 12x = -9

Answer 1

x^2 + 12x = -9
x^2 + 12x +9 = 0

Answer 2

so its 12?

Answer 3

no i just rearranged it ,

Answer 4

so whats the answer

Answer 5

Do you know how to solve it?

Answer 6

no

Answer 7

6 & 2

Answer 8

SOrry I meant to say what two numbers do you add to get 12

Answer 9

You can pick any two.

Answer 10

to complete a square can be thought of geometrically as:

notice that 12x divided in half gives us equal side lengths of 6x and 6x

now all we need to do is determine what value makes the square complete: