## Precalculus: Mathematics for Calculus, 7th Edition

$(2,-2)$
To solve a pair of equations in two variables graphically, first put each equation in function form, $y=f(x)$. 1. Graph the equations on a common screen. 2. Find the points of intersection of the graphs. The solutions are the x- and y-coordinates of the points of intersection. --------- $\left.\begin{array}{ll} x-y=4\ \ /-x & 2x+y=2\ \ /-2x\\ -y=4-x\ \ /\times(-1) & y=2-2x\\ y=x-4 & y=-2x+2 & \end{array}\right.$ 1. Graphed with desmos.com online calculator (see image below) 2. There is an intersection point, exactly one solution, $(2,-2)$