Solve -129*b + 315*b + 4800 = -134*b for b.
Solve this plz.

A: -15

Solve -47*s + 7820 = -387*s for s.
Solve this plz.

A: -23

Solve 78753*b - 58600 = 75823*b for b.
Solve this plz.

A:
20