Write down the solution for this math problem: Solve 0 = -111*u + 110*u - 5 for u.
answer: -5

Write down the solution for this math problem: Solve 0 = -4*u - 4 + 28 for u.
answer: 6

Write down the solution for this math problem: Solve -4*d + 111 + 108 = 219 for d.
answer: 0

Write down the solution for this math problem: Solve -7902 = -780*i + 7698 for i.
answer:
20