[tex] \left \{ {{3a-b=3} \atop {a+3b=11}} \right. \\ \left \{ {{3a-b=3} \atop {a=-3b+11}} \right. \\ 3(-3b+11)-b=3 \\ (3*-3b)+(3*11)-b=3 \\ -9b+33-b=3 \\ -10b+33=3 \\ -10b+33-33=3-33 \\ -10b=-30 \\ -10b/-10=-30/-10 \\ b=3[/tex]
Then plug b into one of your equations. I'm choosing a=-3b+11.
[tex]a=-3b+11 \\ a=-3(3)+11 \\ a=-9+11 \\ a=2[/tex]
The answer is a = 2, b = 3. This is also sometimes accepted as (2,3).
Hope this helps!
