Решите систему уравнений номер 9 ПЛИИЗ надо до 18 15 я на уроке ПЛИИЗ умоляю

[latex] \left \{ {{x-y=2} \atop {2x-3y=-1}} \right. [/latex] х=2+у 2(2+у)-3у=-1 4+2у-3у=-1 4-у=-1 у=4+1 у=5 х=2+5=7 Ответ: (7;5) [latex] \left \{ {{4x=-6y} \atop {7y-2x=20}} \right. [/latex] х=-6у/4 7у-2*(-6у/4)=20 7у-12у/4=20 7у-3у=20 4у=20 у=20:4=5 х=-6*5/4=-7,5 Ответ: (-7,5;5) [latex] \left \{ {{8x-3y=7} \atop {3x+y=9}} \right. [/latex] у=9-3х 8х-3*(9-3х)=7 8х-27+9х=7 17х=7+27 17х=34 х=34:17=2 у=9-3*2=3 Ответ: (2;3) [latex] \left \{ {{2(x+y)-x=-6} \atop {3x-(x-y)=0}} \right. [/latex] [latex] \left \{ {{2x+2y-x=-6} \atop {3x-x+y=0}} \right. [/latex] [latex] \left \{ {{x+2y=-6} \atop {2x+y=0}} \right. [/latex] х=-6-2у 2*(-6-2у)+у=0 -12-4у+у=0 -3у=12 у=12:-3=-4 х=-6-2*(-4)=2 Ответ: (2; -4) [latex] \left \{ {{x+5y=-2} \atop {0.5x-y=6}} \right. [/latex] х=-2-5у 0,5*(-2-5у)-у=6 -3,5у=6+1 -3,5у=7 у=7:-3,5=-2 х=-2-5*(-2)=8 Ответ: (8;-2) [latex] \left \{ {{2x+3(x+y)=11} \atop {7(x+3y)-4y=-23}} \right. [/latex] [latex] \left \{ {{2[+3[+3y=11} \atop {7x+21y-4y=-23}} \right. [/latex] [latex] \left \{ {{5x+3y=11} \atop {3x+17y=-23}} \right. [/latex] х=(11-3у)/5 7*(11-3н)/5+17у=-23 (77-21у)/5+17у=-23 (77-21у)/5+85у/5=-23 (77-64у)/5=-23 77-64у=-23*5 64у=115+77 64у=192 у=192:64 у=3 х=(11-3*3)/5 х=2/5 Ответ: (2/5; 3)