how to put this in vertex form:

Question

-2(2x-1)(x+4)

Answer 1

y= -2(2x-1)(x+4)
-y/2 = (2x^2 +7x -4 )
-y/4 = x^2 +7/2 x -2
-y/4 + 2 = x^2 +7/2 x
-y/4 + 2 + 49/16 = x^2 + 7/2 x + 49/16
-y/4 + 81/16 = (x+7/4)^2
-1/4 (y-81/4) = (x+7/4)^2
(-7/4, 81/4)