The height in feet of a diver above the surface of a pool is given by the equation h= -16t^2 +20t +12, where t is the time in seconds after the diver jumps. 1. how many seconds after the jumping is the diver’s height 8 meters? 2. how long does it take the diver to reach the water?

#1) 1.4 seconds
#2) 1.7 seconds

For #1, we set the function equal to 8:
8 = -16t² + 20t + 12

To solve a quadratic equation we want it equal to 0, so subtract 8 from both sides:
8 - 8 = -16t² + 20t + 12 - 8
0 = -16t² + 20t + 4

Use the quadratic formula to solve this:


Since a negative time makes no sense, the answer is 1.4

For #2,


Since negative time makes no sense, the answer is 1.7.

Horizontal change or the change of x