X-3y=8

2x-y=6

X=8+3y

2x-y=6

2(8+3y)-y=6

16+6y-y=6

5y=-10

Y=-2

X= 8+3*(-2)

X= 2

[tex]\displaystyle \left \{ {{x-3y=8} \atop {2x-y=6}} \right. \\\\\left \{ {{x=8+3y} \atop {2x-y=6}} \right. \\\\2(8+3y)-y=6\\y=-2\\x=8+3(-2)\\x=2\\(x,y)=(2,-2)[/tex]