Chapter 4 - Section 4.2 - Solving Systems of Linear Equations by the Substitution Method - Exercise Set - Page 300: 2

{(5,1)}

y=2x-9 Plug this value for y into the other equation. x+3y=8 x+3(2x-9)=8 x+3(2x)-3(9)=8 x+6x-27=8 7x-27=8 7x=8+27 7x=35 x=$\frac{35}{7}$ x=5 Plug this back into the first equation to find y. y=2(5)-9 y=10-9 y=1 Therefore the solution is {(5,1)}