Question:
Solve 0 = -231*a + 212*a + 152 for a..

Answer:
8

Question:
Solve -7643*o = -7633*o + 10 for o..

Answer:
-1

Question:
Solve 0 = 542*f - 2046*f - 2219*f + 407*f - 56372 for f..

Answer:
-17

Question:
Solve -23*i = -26*i - 9 for i..

Answer:
-3