The ball hits the ground when the height h(t) = 0 , so
-16t^2 + 80t = 0
-16t(t - 5) = 0
t- 5 = 0 or -16t^2 = 0 ( here t = 0 which corresponds to when ball is thrown)
t - 5 = 0 gives:-
t = 5 seconds (answer)
Answer:
Answer is -7 Hope this helps :D
Step-by-step explanation:
4m+9+5m-12=42
9m-3=42
Divide bothsides by 9.
9m/9 -3/9=-0.3=-4
m=-4
