Write down the solution for this math problem: Solve 530*f - 280*f - 173*f - 3677 = 1482 for f.
answer: 67

Write down the solution for this math problem: Solve -440 + 510 = -10*o for o.
answer: -7

Write down the solution for this math problem: Solve 0 = -79*i - 6*i + 425 for i.
answer: 5

Write down the solution for this math problem: Solve -63 + 91 = 7*r for r.
answer:
4