Chapter 4 - Review Exercises - Page 337: 20

infinitely many solutions {(x,y)|4x+y=5}

4x+y=5 4x-4x+y=5-4x y=5-4x Plug this value for y into the other equation 12x+3y=15 12x+3(5-4x)=15 12x+15-12x=15 12x-12x+15=15 15=15 Since this is a true statement without variables, this system has infinitely many solutions. The solution set is represented by either of the equations for example, {(x,y)|4x+y=5}