Question:
Solve 0 = 3*m + 2*m + 20 for m..

Answer:
-4

Question:
Solve 0 = -15*b + 213 - 363 for b..

Answer:
-10

Question:
Solve 30*u - 304 - 189 = 47 for u..

Answer:
18

Question:
Solve 862 + 138 = 200*c for c..

Answer:
5