Write down the solution for this math problem: Solve -3660*c = -3831*c + 513 for c.
answer: 3

Write down the solution for this math problem: Solve 0 = 25*r + 33*r - 53*r for r.
answer: 0

Write down the solution for this math problem: Solve -142*u - 2384 = -8916 for u.
answer: 46

Write down the solution for this math problem: Solve -1089 = -20*k - 101*k for k.
answer:
9