Question:
Solve 12 = -157*u + 155*u for u..

Answer:
-6

Question:
Solve -3*j = -9*j - 30 for j..

Answer:
-5

Question:
Solve 0 = 100*d + 13170 - 14670 for d..

Answer:
15

Question:
Solve 186*f - 179*f - 16307 = -790*f - 367 for f..

Answer:
20