Substitution for x+2y=11 and -8x+6y=22

x+2y=11
can be written as
x = 11 - 2y

substitute x into the other equation
-8(11 - 2y) + 6y=22
simplify

-88 + 16y + 6y = 22
-88 + 22y = 22
+88           +88            isolate y

22y = 110
   
22        22

y = 5! now add Y into the equation to find X

-8x+6(5)=22
-8x+30=22
     - 30 -30
-8x = -8
 
-8     -8

x = 1                   (1,5) Is the solution