Chapter 4 - Section 4.2 - Solving Systems of Linear Equations by the Substitution Method - Exercise Set - Page 300: 16

{(x,y)|y=3x-4} infinitely many solutions

y=3x-4 Plug this value for y into the other equation. 9x-3y=12 9x-3(3x-4)=12 9x-3(3x)-3(-4)=12 9x-9x+12=12 12=12 Since this statement is true, there are infinitely many solutions and the solution set contains either of the equations from the system. For example, {(x,y)|y=3x-4}.