-2x+9y=5
substitute x=11
-2(11) + 9y =5
-22 +9y =5
add 22 to each side
22-22 +9y =5+22
9y = 27
divide each side by 9
9y/9 = 27/9
y =3
Replace all the x's in the equation with 11.
-2(11)+9y=5
Multiply -2 times 11
-22+9y=5
Then add 22 to both sides of the equation.
9y=27
Then divide both sides by 9.
So you get y=3.