Answer:
69
Step-by-step explanation:
I don't know bro but you are the one who has been a good baby
Answer:
0,70 s
Step-by-step explanation:
We have to solve the associated equation:
-16t^2 + 48t + 64 = 90
1) divide each member by 2
-8t^2 + 24t + 32 = 45
2) add at both member -45
-8t^2 + 24t + 32 -45 = 45-45
-8t^2 + 24t - 13 = 0
3). multiply the two members by -1
8t^2 - 24t + 13 = 0
4) find Δ/4 with the reduce formula
Δ/4 = 144 -104 = 40
5) find the approximate solutions with the reduce formula
t1 = (12 + 6,42)/8 = 2,29 s
t2 = (12 - 6,42)/8 = 0,70 s
we have to take the smallest value because the biggest describe when the rocket will reach 90 feet when it is descending
