Answer:
15 3/4t^2 + 5 1/4
Explanation:
h(t)=-16t^2+400
We can add 400 then - 64 and show as 8^2
= h(t)=-16t^2+400 - 8^2
But we also need to change 16t^2;
We divide 64 into 16 = 16/64 =0.25
and show 16t^2 changes by 0.25 = 1/4
15 3/4t^2 + 400-64
Can now look like
15 3/4t^2 + 5 1/4
As 5 1/4 = 64 x 5 1/4 = 336
We'll be assuming this is with simple interest.
now, a year has 12 months, thus in 18 months there are 18/12 years.

Since he can run 1/4 of a mile in 2.5 minutes, he will run a full mile in 4*2.5 =10 minutes, assuming he runs at a steady speed.
Answer:
9a+20=7a-20
2a=4-20
a=2-10
A= -8
Step-by-step explanation: