Question:
Solve -6*c - 30 = -12*c for c..

Answer:
5

Question:
Solve 0 = 129*i - 131*i - 6 for i..

Answer:
-3

Question:
Solve 8*o - 7*o = 4*o for o..

Answer:
0

Question:
Solve -30 - 106 = 34*v for v..

Answer:
-4