Q: Solve:
Solve 9*d - 15*d = -30 for d.

A: 5

Q: Solve:
Solve -577*f - 374*f - 19893 = 21*f + 75*f for f.

A: -19

Q: Solve:
Solve 1893*b + 153*b - 94976 = -999*b + 77*b for b.

A:
32