What is the solution for x + 3y = 5 and x - y = - 1

You can solve this system of equations by eliminating the variable y, if you multiply the second equation by 3

x + 3y = 5

3x - 3y = - 3

then add them together to get 4x = 2

so x = 0.5 or 1/2

then substituting that value into the either of the original equations gives

y = 3/2