Question

can -2x^2 + 4x +4 be done by completing the square?

Answer 1

ANY quadratic equation can be solved by completing the square.

Answer 2

how do i do that?

Answer 3

first, try to make the co-efficient of x^2 as 1.
-2x^2 + 4x +4 = -2 (x^2...........) ?

Answer 4

-2(x^2 - 2x - 2)

Answer 5

yes, thats correct.
so, -2x^2 + 4x +4 =0
x^2 - 2x - 2 = 0
now, divide the co-efficient of 'x' , which is -2 , by 2
so you get -1 , if you square it, you get +1
so, x^2 - 2x - 2 = 0 ----> (x^2-2x+1) -2-1 =0
git this ?

Answer 6

yeah, i got up to there but im confused what to do next

Answer 7

sorry for late reply.
now (x^2-2x+1) is a perfect square.
(x- 1)^2 -3 =0
(x- 1)^2 = 3
taking square root on both sides,
x-1 = +sqrt 3 or x-1 = -sqrt 3
got this ?
now finding 2 values of x is pretty simple...