Write down the solution for this math problem: Solve -21 + 9 + 8 = -2*a for a.
answer: 2

Write down the solution for this math problem: Solve -8750 = -397*n + 7663 - 6091 for n.
answer: 26

Write down the solution for this math problem: Solve 78*d - 47*d = 44*d + 182 for d.
answer: -14

Write down the solution for this math problem: Solve -661 - 1679 = 78*n for n.
answer:
-30