Помогите, пожалуйста, решить систему

Решите задачу:

$\left \{ {{(x+2y)^2-2(x-2y)=11} \atop {5(x+2y)+x-2y=-18}} \right. \\\\x+2y=u\; ,\; x-2y=v\\\\ \left \{ {{u^2-2v=11} \atop {5u+v=-18}} \right. \; \left \{ {{u^2-2(-5u-18)-11=0} \atop {v=-5u-18}} \right. \; \left \{ {{u^2+10u+25=0} \atop {v=-5u-18}} \right. \; \left \{ {{(u+5)^2=0} \atop {v=-5u-18}} \right. \\\\ \left \{ {{u=-5} \atop {v=25-18=7}} \right. \; \left \{ {{x+2y=-5} \atop {x-2y=7}} \right. \; \left \{ {{x+2y=-5} \atop {4y=-12}} \right. \; \left \{ {{x=-5-2y} \atop {y=-3}} \right.$

$\left \{ {{x=-5+6=1} \atop {y=-3}} \right. \\\\Otvet:\; (1,-3).$