Do you mean factorize? It's a bit of a difficult one in isolation because it depends what numbers you're allowed to use in your answer - integers, rational numbers, surds etc!
Is this the whole of the question, or is there more to it?
What are your thoughts? Can you factorize x^2 - 9 for example?
Can you write the whole equation in detail? the one in the title is confusing. What is the power in x^2-11? maybe x² - 11? and where is the right side of the equation? an equation has always two sides.