[tex]x = y - 3
[/tex]
[tex]\text{substitution}[/tex]
[tex]2x + y = 12[/tex]
Start with the original equation
[tex]2x+y=12
[/tex]
[tex]2(y-3)+y=12
[/tex]
[tex]3y-6=12
[/tex]
Solve for y in [tex]3y-6=12 [/tex]
[tex]3y-6=12
[/tex]
[tex]3y=12+6
[/tex]
[tex]3y=18
[/tex]
[tex]y= \dfrac{18}{3} [/tex]
[tex]y=6[/tex]
Substitute [tex]y=6[/tex] into [tex]x=y-3[/tex]
[tex]x=y-3[/tex]
[tex]x=6-3
[/tex]
[tex]x= 3[/tex]
Therefore, [tex]y=6[/tex] and [tex]x= 3[/tex].
