Solve, using the substitution method.

m + n = 5

m - n = 3

M + n = 5

m = n + 3

plug m=n+3 into the first equation.

(n+3) + n=5

n+n+3=5

2n+3=5

2n=2

n=1

First rearrange the first equation and solve it for 'm':

m + n = 5

Subtract n to both sides:

m = - n + 5

Now plug in - n + 5 for 'm' in the 2nd equation:

-n + 5 - n = 3

Combine like terms:

-2n + 5 = 3

Subtract 5 to both sides:

-2n = - 2

Divide - 2 to both sides:

n = 1

Now we can plug this back into any of the two equations and solve for 'm':

m + n = 5

m + 1 = 5

Subtract 1 to both sides:

m = 4

So our full answer is (4, 1)