Chapter 8 - Systems of Linear Equations and Problem Solving - 8.2 Solving by Substitution or Elimination - 8.2 Exercise Set - Page 516: 23

$(2,0)$

Isolate $b$ in eq.$2$ $ 3a-b=6\qquad$ ... add $b-6$ $ 3a-6=b\qquad$ ... divide with 2 $ b=3a-6\qquad$ (*) Replace $b$ with $3a-6$ in the other equation: $ 2a+6(3a-6)=4\qquad$ ... and solve for $a$. $2a+18a-36=4$ $20a=40$ $a=2$ Now, back-substitute into (*) $b=3(2)-6=0$ Form an ordered pair $(a,b)$ as the solution to the system $(2,0)$