Q: Solve:
Solve 10*q - 9 = 19*q for q.

A: -1

Q: Solve:
Solve -35*r - 95*r = -910 for r.

A: 7

Q: Solve:
Solve 4*f + 5*f + 21*f + 360 = 0 for f.

A:
-12