2х+3(х+у)=11 (знак системы) 7(х+3у)-6х=-59 помогите решить

[latex] \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 \\ \\ x=-59-21y \\ \\ 5(-59-21y)+3y=11 \\ -295-105y+3=11 \\ -102y=306 \\ y=-3 \\ \\ x=-59-21*(-3)=-59+63=4 [/latex]