Find a combination calculator, but in 14 and 4, choose combinations (not permutations) and you will see the number
Assuming that he doesn't pay taxes on what he owes, then his remaining balance to pay is $819.48. I hope this helped.
2x + 3y = 18
3y = 18 -2x
y = (18/3) - (2/3)x
y = 6 - 2/3x
y =-2/3x + 6