For example, with that, let's check your last attempt:
Oops, not yet correct. Can you tell what you did wrong from the result? That last term was from multiplying the last part of each factor (the 11^2) together. What would need to be multiplied to make 11^2 rather than 11^4?
That is not factoring - thats solving - you need (x+??)(x-??) - don't give up, just try again!
Have a read of this Difference of two squares - Wikipedia, the free encyclopedia