Question:
Solve -4*s = -5*s + 1 for s..

Answer:
1

Question:
Solve -5321 = -304*f - 23*f + 12991 for f..

Answer:
56

Question:
Solve -4*a - 20 = -8*a for a..

Answer:
5

Question:
Solve 66*w + 372 = -43*w + 16*w for w..

Answer:
-4