Problem: if 7 a - 3 b = 10 b + 50 = - 12 b - 2 a , what is the value of 9 a + 9 b ?
Rationale: "( i ) 7 a - 13 b = 50 ( ii ) 2 a + 22 b = - 50 adding ( i ) and ( ii ) : 9 a + 9 b = 0 the answer is c ."
annotated_formula: divide(const_0_33, const_1000)