Determine if the expression is a perfect square and if it is, factor it. A2 – 8 a +16 A. (a +4) (a – 4) B. (4 a +1) 2 C. (a – 4) (a – 4) D. Not a perfect square

The answer is C. With FOIL, F would be a*a (a^2), O would be a*-4 (-4 a), I would be -4*a (-4 a), and L would be -4*-4 (16). Both -4 a and -4 a have the same variable (a) so would combine to make -8 a. You would then end up with a^2-8 a +16.