Verified answer

Follow the FOIL method (First, Outside, Inside, Last)

(2x+3)(2x-3) = 4x^2-6x+6x-9 = 4x^2-9

2x+3(2x-3) = 2x+6x-9 = 8x-9

(2x-3)(-2x-3) = -4x^2-6x+6x+9 = -4x^2+9

(a + b + c)(d - e) = advert - ae + bd - be + cd - ce attempt to word the order that the words have been elevated above, and do the comparable to your project. for example, on your case, the a=x^5, d=x^2, so the 1st term is advert=x^5*x^2 = x^7. are you able to take it from there?