Write down the solution for this math problem: Solve 9*c = 6*c for c.
answer: 0

Write down the solution for this math problem: Solve 12*c = 7*c + 5 for c.
answer: 1

Write down the solution for this math problem: Solve 55*w + 56*w - 96 = 135*w for w.
answer: -4

Write down the solution for this math problem: Solve 0 = -69*d + 48*d + 231 for d.
answer:
11