Question:
Solve 21 - 51 = 6*r for r..

Answer:
-5

Question:
Solve -27422*t + 86460 = -24540*t for t..

Answer:
30

Question:
Solve 224 + 860 + 3260 = 181*u for u..

Answer:
24

Question:
Solve 6*a - 3520 = 145*a + 21*a for a..

Answer:
-22