Answer :
Answer:
Step-by-step explanation:
The rock will hit the surface when its height equals zero.
t^2-8t-10=0
t^2-8t=10
t^2-8t+16=10+16
(t-4)^2=26
t-4=+(26^(1/2))
t=4+(26^(1/2))
t=9.1s
Answer:
Step-by-step explanation:
The rock will hit the surface when its height equals zero.
t^2-8t-10=0
t^2-8t=10
t^2-8t+16=10+16
(t-4)^2=26
t-4=+(26^(1/2))
t=4+(26^(1/2))
t=9.1s