Write down the solution for this math problem: Solve 42*d + 6*d = 8*d + 520 for d.
answer: 13

Write down the solution for this math problem: Solve 255*d - 206*d = 931 for d.
answer: 19

Write down the solution for this math problem: Solve -1680*v = -885*v - 898*v + 412 for v.
answer: 4

Write down the solution for this math problem: Solve 0 = 11*w - 43530 + 43728 for w.
answer:
-18