Question

How do you complete a square

Answer 1

Suppose you have x^2 + 3x - 2 = 0
They ask you to complete the square.

Answer 2

What you do is to ask, how could x^2 + 3x result from doing (x-a)^2

Answer 3

So I should make it 4x, sorry.

Answer 4

what is a?

Answer 5

some number we are going to find

Answer 6

okay

Answer 7

So going with x^2 + 4x, that would be
(x+2)^2 = x^2 + 4x + 4

Answer 8

But if our original equation was x^2 + 4x - 2
we don't have the 4 we need…

Answer 9

So what we do is to add 4 and then subtract it again right away. To keep the equality.
x^2 + 4x - 2 = x^2 + 4x + 4 - 2 - 4 = 0
(x + 2)^2 -6 = 0

Answer 10

thank u