[tex]\displaystyle\left \{ {{3x - y = 17} \atop {2x+3y = -7}} \right. \\\\\displaystyle\left \{ {{y=3x-17} \atop {2x+3y = -7}} \right.[/tex]

Подставляем у во второе уравнение:

[tex]2x+3(3x-17)=-7\\2x+9x-51=-7\\11x=44\\x=4[/tex]

Если [tex]x=4[/tex], то [tex]y=3\times4-17=-5[/tex]

Ответ: (4; -5)

Verified answer

[tex]\displaystyle\bf\\\left \{ {{3x - y = 17 \: \: | \times 3 } \atop {2x + 3y = -7 }} \right. \\ \displaystyle\bf\\ + \left \{ {{9x - 3y = 51} \atop {2x + 3y = - 7 }} \right. \\ \\ 9x + 2x = 51 - 7 \\ 11x = 44 \\ x = 44 \div 11 \\ x = 4 \\ \\ 3 \times 4 - y = 17 \\ 12 - y = 17 \\ y = 12 - 17 \\ y = - 5[/tex]

Ответ: ( 4 ; - 5 )