help me please?

Question

simplify each expression
(3-2√(7))(3+2√7)

Answer 1

(3-2√(7))(3+2√7)
3^2 - (2√7)^2
9 - (2^2)(√7^2)
9 - (4)(7)
9 - 28
= -19

Answer 2

This is a binomial expression:
3^2 - 2^2(7)
9 - 4(7)
9 - 28 = -19

Answer 3

what everyone else said [;