Write down the solution for this math problem: Solve 6*d - 9*d = 7*d for d.
answer: 0

Write down the solution for this math problem: Solve 228*i + 29*i = 172*i + 3910 for i.
answer: 46

Write down the solution for this math problem: Solve 56*k + 97*k - 71 = -10*k + 11665 for k.
answer: 72

Write down the solution for this math problem: Solve -18*c + 15 = 51 for c.
answer:
-2