Write down the solution for this math problem: Solve 157*c - 56*c + 423*c + 13100 = 0 for c.
answer: -25

Write down the solution for this math problem: Solve 36786 = 14*t + 36660 for t.
answer: 9

Write down the solution for this math problem: Solve -9*a + 1176 + 69 = 74*a for a.
answer: 15

Write down the solution for this math problem: Solve -254 - 304 = 70*r + 352 for r.
answer:
-13