Write down the solution for this math problem: Solve 1003*n = 140*n - 3491 - 5139 for n.
answer: -10

Write down the solution for this math problem: Solve 2505*a + 31285 + 3785 = 0 for a.
answer: -14

Write down the solution for this math problem: Solve -1315 = -909*f - 406*f for f.
answer: 1

Write down the solution for this math problem: Solve -10*u - 86 = -16 + 30 for u.
answer:
-10