Question:
Solve 143*r - 4*r = -1390 for r..

Answer:
-10

Question:
Solve 463*l - 238*l - 105 = 246*l for l..

Answer:
-5

Question:
Solve 11*u = -6 - 60 for u..

Answer:
-6

Question:
Solve 14*x + 8 = 18*x for x..

Answer:
2