The given equations are
[tex]-x+2y=15[/tex][tex]8x-2y=20[/tex]Adding both equations
[tex](-x+2y)+(8x-2y)=15+20[/tex][tex]7x=35[/tex][tex]x=5[/tex]Hence we get the value of x by adding the equations.
The coefficients of y of the equations are 2 and -2 respectively. so if we add both equations the y term will vanish.
The answer is
Add to eliminate y.
