A creature on the moon throws a rock off a cliff. The height of the rock above the surface of the moon, in meters, t seconds after it is thrown is given by h(t) = −t^2+ 18t + 10. When does the rock hit the surface of the moon?
When the rock hits the lunar surface h = height = 0
0 = −t^2+ 18t + 10 Use Quadratic Formula to solve for t = throw out negative value a = -1 b = 18 c = 10
\(t = {-b \pm \sqrt{b^2-4ac} \over 2a}\)
