Write down the solution for this math problem: Solve -21*r + 131 = 5 for r.
answer: 6

Write down the solution for this math problem: Solve -9*o = -211 + 184 for o.
answer: 3

Write down the solution for this math problem: Solve -15*k = -27*k + 77*k + 28*k + 6231 for k.
answer: -67

Write down the solution for this math problem: Solve 5*p - 4 = p for p.
answer:
1