Remark
I'm going to interpret this equation as
D = ut + kt² The only difference is the 2.
Solution
Subtract kt² from both sides.
D - kt² = ut Now divide by u on both sides.

The t's cancel out. on the right. You are left with u on the right.

Answer:
59
Step-by-step explanation:
They could buy 59
You solve this by dividing the total amount of money ($2183) by the other amount ($37) which is 59
1 coin is 4 ways
2 coins is 4*3 ways
3 coins is 4*3*2 ways
4 coins is 4*3*2*1 ways
so total is 4+12+24+24=64 sums
-18 +30s -72t +12u is the answer