QUESTION: Math problem: Solve -20*r + 24 = 164 for r.
ANS: -7
QUESTION: Math problem: Solve 12*v - 121 + 85 = 0 for v.
ANS: 3
QUESTION: Math problem: Solve -411 - 854 = 115*x for x.
ANS: -11
QUESTION: Math problem: Solve 24*a - 1729 = -21*a + 553 + 778 for a.
ANS:
68