Hey there!
The answer is C.
To factor an expression, you take the root (same as exponent variable has) of the terms and put them into parantheses. We can also check the choices to see if they're correct by solving them.
A is incorrect, because if you solve it, you would have [tex]x^2-121[/tex]
B is incorrect, because if you solve it, you would have [tex]121x-x^2[/tex]
C is correct, because if you solve it, you would have [tex]121-x^2[/tex]
D is incorrect, because it CAN be factored.
Have a super awesome day! :)
