add the two equations to get
4y = 28
y = 7
so, x = 22
-x+5y=13
x-y=15
Solve by using process of elimination.
2 answers
visit
http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
to see the intermediate steps
http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
to see the intermediate steps