I am having a hard time - please guide me to solve by the substitution method.
5m + n = 36
m -7n = 36
A big ty:)
Since m = 7n + 36,
substitute 7n + 36 for m in the first equation.
That should lead to
35n + 180 + n = 36
which is the same as
36n = -144
n = -4
Now solve for m with either of your first two equations.