Q: Solve:
Solve -7*r + 172*r = -262*r + 4697 for r.

A: 11

Q: Solve:
Solve 7*c - 204 = -23*c - 4*c for c.

A: 6

Q: Solve:
Solve -21521*z = -21675*z - 3388 for z.

A:
-22