Which of the following is the maximum value of the equation y=-2x^2-3x+4

A. - 3/4

B. 5 1/8

C. 5/8

D. 1 3/4

Y=-2x^2-3x+4

dy/dx=-4x-3, d2y/dx2=-4

When the velocity, dy/dx=0, then y (x) is at an absolute maximum because the acceleration is a constant negative, - 4.

dy/dx=0 only when - 4x-3=0, - 4x=3, x=-3/4

y (-3/4) = 5.125

So the maximum value of y is 5 1/8