Applications of Quadratic Linear equations

Question

For the following problem, use the function: h(t)=-16t^2+ v o t+ s

Standing on the edge of a cliff, Fernando throws a rock upward from a height 160 feet above the water at a speed of 48 feet per second. How long will it take for the rock to land in the water?

Answer 1

h(t) = -16t^2+ 48t+ 160 = 0

solve for t= seconds when rock hits the water

divide by -16

t^2 -3t -10 = 0

factor

(t-5)(t+2) = 0

t=5 seconds to splash land