The output is eleven more then the input

The input is known as x and the output is known as y in math.
So you’re stating that we’re making the equation equal the output, y, and we’re adding based off of the word “more”. Now that we know we’re adding, we have to find what we are adding together. We are adding x and 11 is that it equals y. Note that x and y could be many different variables and values.
Y= x+11