Solve f = -2*r - 2*f - 21, 2*f + 13 = -r for r.

-3

Solve 5*x - 2*x = 0, 1 = -j - 5*x for j.

-1

Solve 0 = 3*v + 12*f - 9*f - 9, 5*f = -v + 19 for v.

-1

Solve -17*s + 16*s - 2*w + 6 = 0, -w = -s for s.

2

Solve -5*x + 1 = -3*v, x - 3*v = 14 - 9 for x.

-1

Solve 2*i = w - 15, 4*i = i - 3*w for i.

-5

Solve 5*i + 3*f = -6, 9*i - 5*f = 8*i - 18 for i.

-3

Solve -4*f + 3*y = 7, 3*y = 2*f + 5*y for f.

-1

Solve -3*w + 1 = -4*n + 2, -n = 3*w - 4 for w.

1

Solve 4*m + 3 + 3 = -2*r, -2*r = -m - 9 for r.

3