Solve -1595 + 4597 + 21743 = -3298*u - 8235 for u.
Solve this plz.

A: -10

Solve -13*b = -7*b + 25*b + 248 for b.
Solve this plz.

A: -8

Solve 163*c + 390*c = 166*c + 4644 for c.
Solve this plz.

A:
12