All you have to do is subtract 11 from both sides. That way, you have only “x” on the left, and 3-11 on the right, while x still keeps its original value.
x = 3-11
x = -8
We can check it if we plug that into the original equation:
x + 11 = 3
-8 + 11 = 3
11 - 8 = 3
3 = 3, so we got the correct answer.
