Question:
Solve 0 = 4*w + 25 - 9 for w..

Answer:
-4

Question:
Solve -4515 = -45214*b + 44913*b for b..

Answer:
15

Question:
Solve -5086*d + 5146*d = 480 for d..

Answer:
8

Question:
Solve 4*u - 1220 = -1204 for u..

Answer:
4