Write down the solution for this math problem: Solve -20 = 777*x - 781*x for x.
answer: 5

Write down the solution for this math problem: Solve 0 = -4*a + 2 + 14 for a.
answer: 4

Write down the solution for this math problem: Solve -21*x = -70 + 7 for x.
answer: 3

Write down the solution for this math problem: Solve -132*k + 2730 = -270*k + 208*k for k.
answer:
39