Question:
Solve -30*p + 1212 = 51*p + 20*p for p..

Answer:
12

Question:
Solve -717 = -97*r + 2898 - 705 for r..

Answer:
30

Question:
Solve 78 + 62 = 28*b for b..

Answer:
5

Question:
Solve 71*a + 552 - 55 = 0 for a..

Answer:
-7