+4 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 +8t +10. when does the rock hit the surface of the moon?
+122 Easier to understand: 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 \(h(t) = -t^2 +8t +10\). when does the rock hit the surface of the moon?
+36916 When the rock hits the surface h = 0
0 = -t^2 +8t + 10 use quadratic formula a = -1 b = 8 c = 10
\(t = {-b \pm \sqrt{b^2-4ac} \over 2a}\) You will get TWO values of 't' ....throw out the negative value
