Question 454876
{{{ 2x=2y=20}}}

I guess, you have 


{{{ 2x-2y=20}}}......simplify first; both sides divide by {{{2}}}

{{{ 2x/2-2y/2=20/2}}}

{{{ x-y=10}}}

write it in slope-intercept form {{{y=mx+-b}}}, where {{{m}}} is a slope: or solve for {{{y}}}

{{{ y=x-10}}}........slope-intercept form; as you can see {{{m=1}}}

{{{ graph( 500, 500, -10, 15, -15, 10, x-10) }}}