Question:
Solve 32*u - 39*u - 3180 = -113*u for u..

Answer:
30

Question:
Solve -176 = 39*r - 150 + 676 for r..

Answer:
-18

Question:
Solve -126*d + 9 = -125*d for d..

Answer:
9

Question:
Solve 2210 = -353*n + 12800 for n..

Answer:
30