The question is as followed:

Question

y=-3x^2 + 4x

This is how I solved it:

y=-3x^2 + 4x
y= -3 (x^2 + 4/3x)
y= -3(x^2+4/3x +4/9) + 4/3
y= -3 (x+2/3)^2 + 4/3

The answer sheet said that x = 2/3 but wouldn't it equal -2/3 because there is a -3 before the bracket?

bobpursley · Answer

y=-3x^2 + 4x y= -3 (x^2 + 4/3x)You erred here, it should be y=-3x^2 + 4x y= -3 (x^2 - 4/3x )

Lena · Answer

oh ok thanks so much :)