This is a system of linear equations, and you are to solve for x and y that satisfy both equations.
Write out the first equation: x + 3y = 8. Now mult. the 2nd equation by -1.
combine your result with x+3y=8. x will disappear. Solve for y.
Subst. this y value into either of the original equations to find x.
Write your answer in the form (x,y).