Question:
Solve 10*o - 11 = -1 for o..

Answer:
1

Question:
Solve 21 = -8*c + c for c..

Answer:
-3

Question:
Solve 17*s + 425 - 912 = -266 for s..

Answer:
13

Question:
Solve -8*k = 74*k - 691 - 1537 - 232 for k..

Answer:
30