Which products result in a difference of squares or a perfect square trinomial? Check all that apply.
(5x+3)(5x - 3)
(7x + 4)(7x + 4)
(2x + 1)(x + 2)
(4x – 6)(x + 8)
(x - 9)(x – 9)
(-3x – 6)-3x+6)

Step-by-step explanation:

Expressions of the form (a +b)(a +b) will result in a perfect square trinomial, because both binomial factors are identical.

Expressions of the form (a +b)(a -b) will result in a difference of squares.

Match the offered choices to either one of these forms, and they will be included in the answer set.

  (5x + 3)(5x - 3) -- difference of squares

  (7x + 4)(7x + 4) -- perfect square

  (2x + 1)(x + 2) -- nothing special

  (4x-6)(x + 8) -- nothing special

  (x - 9)(x - 9) -- perfect square

  (-3x-6)(-3x+6) -- difference of squares