Question:
Solve -21*f + 91 = 7 for f..

Answer:
4

Question:
Solve 350251*i - 350210*i - 1763 = 0 for i..

Answer:
43

Question:
Solve -114*o - 60*o + 2256 = 14*o for o..

Answer:
12

Question:
Solve -21038*u = -18492*u + 33098 for u..

Answer:
-13