After how many seconds will the ball hit the ground? h = -16t^2 + 12t + 40

2 seconds

Step-by-step explanation:

h = -16t^2 + 12t + 40

by the time the ball hit the ground, height (h) = 0

0 = -16t^2 + 12t + 40

solve time (t) using quadratic equation:  ax^2+bx+c=0

      - b ±

x = -----------------------------

              2a

where:

a = -16

b = 12

c = 40

plugin values into the formula

      - 12 ±

t = ----------------------------------

                   2 (-16)

t = -5/4 , t = 2

therefore, the ball will hit the ground in 2 seconds

power property.