Question:
Solve 23*r - 492 = 13*r - 31*r for r..

Answer:
12

Question:
Solve 43*a = -48*a + 88*a for a..

Answer:
0

Question:
Solve -11 = -4*d - 3 for d..

Answer:
2

Question:
Solve 35 + 655 = -69*z for z..

Answer:
-10