Q: Solve:
Solve 0 = 11*r - 76 + 21 for r.

A: 5

Q: Solve:
Solve 7179*k - 5766*k - 57933 = 0 for k.

A: 41

Q: Solve:
Solve -894*f + 81 = -903*f for f.

A:
-9