Write down the solution for this math problem: Solve 261 - 107 = -22*p - 66 for p.
answer: -10

Write down the solution for this math problem: Solve 3216 = 421*r - 6467 for r.
answer: 23

Write down the solution for this math problem: Solve 2*k - 54*k + 9*k = 66*k for k.
answer: 0

Write down the solution for this math problem: Solve 9*r - 69 = -14*r for r.
answer:
3