Q: Solve:
Solve 8*s - 30*s - 63 = -13*s for s.

A: -7

Q: Solve:
Solve 86*r - 329 = 576 + 950 - 737 for r.

A: 13

Q: Solve:
Solve 0 = 25*o - 15*o - 8*o - 8 for o.

A:
4