[tex]\bf \begin{array}{|c|ll} \cline{1-1} slope-intercept~form\\ \cline{1-1} \\ y=\underset{y-intercept}{\stackrel{slope\qquad }{\stackrel{\downarrow }{m}x+\underset{\uparrow }{b}}} \\\\ \cline{1-1} \end{array}~\hspace{6.5em} \begin{cases} 2x-y=-5\implies &2x+5=y\\\\ 2x+y=5\implies &y=-2x+5 \end{cases}[/tex]
let's notice, the slope for the 1st equation is "2", with a y-intercept of "5".
the slope of the 2nd equation is "-2", and the y-intercept is the same as the 1st one.
different slopes, mean they touch each other, and since both area linear equations, they touch each other once, incidentally enough at y = 5.
