Найдите решение системы уравнений способом подстановки . уравнения 2 и 4 номер 1499 ...

Решите задачу:

$\left \{ {{3(x+2y)-y=27} \atop {4(x+y)-3x=23}} \right. \left \{ {{3x+6y-y=27} \atop {4x+4y-3x=23}} \right. \left \{ {{3x+5y=27} \atop {x+4y=23}} \right. \left \{ {{3(23-4y)+5y=27} \atop {x=23-4y}} \right.$

$\left \{ {{69-12y+5y=27} \atop {x=23-4y}} \right. \left \{ {{69-7y=27} \atop {x=23-4y}} \right. \left \{ {{-7y=-42} \atop {x=23-4y}} \right. \left \{ {{y=6} \atop {x=23-4*6}} \right. \left \{ {{y=6} \atop {x=-1}} \right.$

$\left \{ {{2x+3(x+y)=11} \atop {7(x+3y)-6x=-59}} \right. \left \{ {{2x+3x+3y=11} \atop {7x+21y-6x=-59}} \right. \left \{ {{5x+3y=11} \atop {x+21y=-59}} \right. \left \{ {{5(-59-21y)+3y=11} \atop {x=-59-21y}} \right.$

$\left \{ {{-295-105y+3y=11} \atop {x=-59-21y}} \right. \left \{ {{-102y=306} \atop {x=-59-21y}} \right.\left \{ {{y=-3} \atop {x=-59-21*(-3)}} \right.\left \{ {{y=-3} \atop {x=-59+63}} \right.\left \{ {{y=-3} \atop {x=4}} \right.$