QUESTION: Math problem: Solve 0 = -15*r + 13*r + 10 for r.
ANS: 5
QUESTION: Math problem: Solve 40 - 43 = -3*o for o.
ANS: 1
QUESTION: Math problem: Solve -41*y - 529 = -10*y + 91 for y.
ANS: -20
QUESTION: Math problem: Solve -502*d + 46*d = 9120 for d.
ANS:
-20