Одна система

Решите задачу:

$\left \{ {{cos( \pi y)= x^{2} -6x+10} \atop {x+2y=11}} \right. \\ \\ \left \{ {{cos( \pi y)= (x^{2} -6x+9)+1} \atop {x+2y=11}} \right. \\ \\ \left \{ {{cos( \pi y)= (x-3)^2+1} \atop {x+2y=11}} \right. \\ \\ \left \{ {{x=3, cos( \pi y)=1} \atop {x+2y=11}}\right.\\ \\ \left \{ {{x=3} \atop {y=4, \pi y=2 \pi k, kEZ}}\right. \\ \\ \left \{ {{x=3} \atop {y=4, y=2k, kEZ}}\right.\\ \\ \left \{ {{x=3} \atop {y=4}}\right.$