А) х+у=11 2х-у=-5 б) 5х-4у=8 х-4=2 Помогите пожалуйста! Полный ответ

Решите задачу:

$\left \{ {{x+y=11} \atop {2x-y=-5}} \right. + \left \{ {{x+y=11} \atop {2x-y=-5}} \right. (x + y) + (2y - 11) = 11 - 5 3x = 6 x = 2 (2) + y = 11 y = 9 ( 2 ; 9 )$

$\left \{ {{5x - 4y = 8} \atop {x - 4 = 2}} \right. \left \{ {{5x - 4y = 8} \atop {x - 6 = 0}} \right. \left \{ {{5(6) - 4y = 8} \atop {x=6}} \right. \left \{ {{-4y + 22 = 0} \atop {x=6}} \right. \left \{ {{y=5.5} \atop {x=6}} \right. ( 6 ; 5.5 )$