Can someone please explain how they got the answer for this problem its in my book:

Directions: Find the amount that should be invested now to accumulate the following amounts, if the money is coupounded as indicated.

$7500 at 12% compounded quarterly for 9 yrs.

answer: $2587.74

X * 1.03^36 = $7500.
X * 2.89828 = 7500
X = ?

? I have no idea