答案是B怎么得呢???求教

Sedulously

An object thrown directly upward is at a height of h feet after t seconds, where h = -16 (t - 3)² + 150. At what height, in feet, is the object 2 seconds after it reaches its maximum height?

A. 6

B. 86

C. 134

D 150

E. 214

答案是B怎么得呢???求教

Sedulously

many  thanks !!!!!!!!!!!!!!!!!!

falcons

一个向下的抛物线，t=3时，it reaches its maximum height。

所以题目所求为t=5,代入即得