Q: What is the solution?
Solve 19*f + 428 - 504 = 0 for f.

A: 4

Q: What is the solution?
Solve -73*z = -77*z - 20 for z.

A: -5

Q: What is the solution?
Solve -15*a + 25*a + 80 = 0 for a.

A:
-8