Solve the system.

{m+n=5

m-n=3

Use the substitution method.

The solution is (4, 1) (

There is no solution.

The solution is (2, - 1) (2, - 1).

There are an infinite number of solutions.

Simplify any of the equations:

m=3+n for example

then put the simplified equation into the other equation that is not simplified:

(3+n) + n=5

simplify:

3+2n=5

2n=2

n=1

plug into the first simplified equation for m:

m=3+n

m=3+1

m=4

answer: (1,4)