Verified answer

Ответ:

2x+y=9

2x+3x-1=9

2x+3x=9+1

5x=10

x=10:5

x=2

Ответ: 2

[tex]\displaystyle\bf\\\left \{ {{y=3x-1} \atop {2x+y=9}} \right. \\\\\\\left \{ {{y=3x-1} \atop {2x+3x-1=9}} \right. \\\\\\\left \{ {{y=3x-1} \atop {5x=9+1}} \right. \\\\\\\left \{ {{y=3x-1} \atop {5x=10}} \right. \\\\\\\left \{ {{y=3\cdot 2-1} \atop {x=2}} \right. \\\\\\\left \{ {{y=6-1} \atop {x=2}} \right. \\\\\\\left \{ {{x=2} \atop {y=5}} \right. \\\\\\Otvet \ : \ (2 \ ; \ 5) \ \ \ \boxed{x=2}[/tex]