Problema Solution
A rock is thrown straight up from a 384 foot cliff. The height of the rock as a function of time is given by the equation h(t)=16t+32t+384. How many seconds until the rock hits the ground?
Answer provided by our tutors
-16t^2+32t+384=0
-t^2+2t+24=0
t^2-2t-24=0
t^2-2t+1=25
(t-1)^2=5^2
(t-1)^2-5^2=0
(t-1-5)(t-1+5)=0
(t-6)(t+4)=0
t is either -4 or 6, and since -4 isn't a possible solution, your solution must be 6 seconds.