The height of a rock thrown off a cliff is given by h(t) = -2t2 + 12t + 14. When does this rock hit the ground?

Question

Thank you!

Answer 1

-2t^2 + 12t + 14. =0
-2(t^2-6t-7) =0
-2(t-7)(t+1) =0
t-7 =0
t = 7
t+1 =0
t = -1

hit ground 7