College algebra

Question

A person standing close to the edge on top of a 32-foot building throws a ball vertically upward. The quadratic function h=-16t^2+124t+32 models the ball’s height about the ground, h, in feet, t seconds after it was thrown.

A.) What is the maximum height of the ball?

Answer 1

-b/(2a) = -124/-32 = 62/16 = 31/8

-16(31/8)^2 + 124(31/8) + 32 =

-16( 961/64) + 124*31/8 + 32 = <--- squares

-961/4 + 124*31/8 + 32 <--- 16 cancels 64

-961/4 + 62*31/4 + 128/4 <--- common denominator of 4; reduces 2nd fraction, changes 3rd

(-961+ 1922 + 128)/4

1089/4 = 272.25