Question

$left { {{4x-y=11} atop {2x+5y=11}} right.$

Answer 1

4x - y = 11    /*5
2x + 5y = 11

20x - 5y = 55
2x + 5y = 11 
-------------------- + 
22x = 66
x = 3

y = 4x - 11 = 4*3 - 11 = 12 - 11 = 1

Ответ
(3; 1)