Solve 15 - 27 = 3*r for r.
Solve this plz.

A: -4

Solve 0 = 27*n - 28*n + 43*n - 504 for n.
Solve this plz.

A: 12

Solve 4538*t - 1050 = 4468*t for t.
Solve this plz.

A:
15