2x + y=19
x - y=2

First, simplify one of the equations for x or y. Then substitue that into the other equation. This will leave you with only one variable in your equation. Rearrange the equation to solve for the variable. Then sub that value back into one of the original equations to get the value of the other variable. Check your work by substituting both of the values into each of the equations to make sure they work.

Thanks.
:)