Write down the solution for this math problem: Solve 2*d + 3*d + d = -12 for d.
answer: -2

Write down the solution for this math problem: Solve -48 = 151*b - 145*b for b.
answer: -8

Write down the solution for this math problem: Solve 3247*i = 3254*i - 49 for i.
answer: 7

Write down the solution for this math problem: Solve 4*s - 8*s - 13*s = 68 for s.
answer:
-4