Q: What is the solution?
Solve -18*c + 9*c = 9 for c.

A: -1

Q: What is the solution?
Solve -100 = -65*f + 45*f for f.

A: 5

Q: What is the solution?
Solve 1591*k + 8165 = 1236*k for k.

A:
-23