Q: Solve 0 = -0*v - 4*v + 20 for v.

A: 5

Q: Solve -417*t = 399*t - 1281*t + 401*t - 6720 for t.

A: -105

Q: Solve -3*d - 60 = -23*d for d.

A: 3

Q: Solve -7 - 9 = -4*t for t.

A:
4