Q: What is the solution?
Solve -5*u - 21 - 4 = 0 for u.

A: -5

Q: What is the solution?
Solve 25*c + 129*c - 8800 = -6*c for c.

A: 55

Q: What is the solution?
Solve 0 = -2*a - 0 - 4 for a.

A:
-2