Q: Solve 25*q - 68 = 7 for q.

A: 3

Q: Solve -19*f + 21*f - 8 = 0 for f.

A: 4

Q: Solve 138403 = 12*r + 139003 for r.

A: -50

Q: Solve 257 - 275 = 9*d for d.

A:
-2