Write down the solution for this math problem: Solve -37*r + 24 = -31*r for r.
answer: 4

Write down the solution for this math problem: Solve 54*o - 66*o = 12 for o.
answer: -1

Write down the solution for this math problem: Solve 30*f - 41*f = 0 for f.
answer: 0

Write down the solution for this math problem: Solve 68*o + 131*o + 215*o - 6217 = 17795 for o.
answer:
58