Q: Solve:
Solve -40*r + 720 = -24*r + 8*r for r.

A: 30

Q: Solve:
Solve 648 = -33*w + 83*w + 31*w for w.

A: 8

Q: Solve:
Solve -3*v - 7*v + 11 = 41 for v.

A:
-3