Multiply the 2nd equation by -1 then add equations together
-1(2x+y=11)
-2x - y = -11
(Adding will eliminate the Y)
3x = 12
------------------------------------
Divide each side by 3
3x ÷ 2 = 12 ÷ 3
x = 4
==================================================================
To find Y substitute 4 for x in 5x+y=23
(5)(4)+y=23
y+20=23
-----------------------------
Add -20 on each side
y+20+-20=23+-20
y = 3
Your answers are x = 4 and y = 3