Q: Solve:
Solve 2045 = -399*f + 221*f - 613 - 1080 for f.

A: -21

Q: Solve:
Solve 127*z + 251 - 177 - 3630 = 0 for z.

A: 28

Q: Solve:
Solve -397 + 145 = -5*s - 13*s for s.

A:
14