QUESTION: Math problem: Solve 138 = 21*c - 67*c for c.
ANS: -3
QUESTION: Math problem: Solve -1984*r + 22412 = -1553*r for r.
ANS: 52
QUESTION: Math problem: Solve -110*s + 45*s = 471 - 406 for s.
ANS: -1
QUESTION: Math problem: Solve 525 = 27*l + 12 for l.
ANS:
19