Chapter 3 - Section 3.1 - Systems of Two Equations in Two Unknowns - Exercises - Page 185: 1

$(2,2)$

Adding the two equations will eliminate y. The resulting equation: $2x=4\qquad/\div 2$ $x=2$ Back substitute into one of the initial equations: $x-y=0$ $2-y=0\quad/+y$ $2=y.$ Solutions are ordered pairs (x,y): $(2,2)$ Check graphically by graphing both lines in the same window and determining the intersection (see image).