<span>If A = James's present age
then
</span><span>his age seven years from now = A - 7
hope it helps</span>
We take the equation <span>d = -16t^2+12t</span> and subtract d from both sides to get
0<span> = -16t^2+12t - d
We apply the quadratic formula to solve for t. With a = -16, b = 12, c = -d, we have
t = [ -(12) </span><span>± √( 12^2 - 4(-16)(-d) ) ] / [2 * -16]</span>
= [- 12 ± √(144-64d) ] / (-32)
= [- 12 ± √16(9-4d)] / (-32)
= [- 12 ± 4√(9-4d)] / (-32)
= 3/8 ±√(9-4d) / 8
The answer to your question is t = 3/8 ±√(9-4d) / 8
First, you need to get to one gallon, which is 37.20 divided by 12. (3.1)
Divide that number by four, which is: 0.775, or 0.78 rounded up to the nearest hundredth.
Hope that helped.
