Question

помогите прошу 1 варіант
​

Answer 1

1)

$\displaystyle \left \{ {{x+3y=8} \atop {3x-4y=11}} \right. < = > \left \{ {{x=8-3y} \atop {3(8-3y)-4y=11}} \right. < = > \left \{ {{x=8-3y} \atop {24-9y-4y=11}} \right. < = > \left \{ {{x=8-3*1} \atop {-13y=11-24}} \right. < = > \left \{ {{x=8-3y} \atop {y=1}} \right. < = > \left \{ {{x=5} \atop {y=1}} \right.$

2)

$\displaystyle \left \{ {{2(x+y)-3(x-y)=3} \atop {3(x+y)-2(x-y)=7}} \right. < = > \left \{ {{2x+2y-3x+3y=3} \atop {3x+3y-2x+2y=7}} \right. < = > \left \{ {{-x+5y=3} \atop {x+5y=7}} \right. < = > \left \{ {{-(7-5y)+5y=3} \atop {x=7-5y}} \right. < = > \left \{ {{-7+5y+5y=3} \atop {x=7-5y}} \right. < = > \left \{ {{10y=10} \atop {x=7-5y}} \right. < = > \left \{ {{y=1} \atop {x=7-5*1}} \right. < = > \left \{ {{y=1} \atop {x=2}} \right.$