2m - n/3 = 5m for n

[math_celebrity]

2m - n/3 = 5m for n

Subtract 2m from each side of the equation:
2m-n/3 - 2m = 5m - 2m
-n/3 = 3m

Multiply each side of the equation by -3 to isolate n:
-3 * -n/3 = -3 * 3m
n = -9m