Question 101409
{{{2x-y=x+y}}} let all {{{x}}} on the left side and {{{y }}}on the right side
{{{2x-x=y+y}}}
{{{x=2y}}}
=> {{{y=(1/2)x}}}

check;
{{{2x-y=x+y}}}     
since {{{y=(1/2)x}}}, 
we will have
     {{{2x}}}–{{{(1/2)x}}}={{{x}}}+{{{(1/2)x}}}

 {{{x+(1/2)x= x+(1/2)x }}} (left and right side are equal)