Question

Which will result in a difference of squares? (–7x + 4)(–7x + 4) (–7x + 4)(4 – 7x) (–7x + 4)(–7x – 4) (–7x + 4)(7x – 4)

Answer 1

a difference of squares
a^2 – b^2 = (a + b)(a – b)
in this case

(–7x + 4)(–7x – 4)

answer
(–7x + 4)(–7x – 4)

Answer 2

(–7x + 4)(–7x – 4) Sign changes in the middle of both parenthesis , so this will result in difference of squares

Explanation:

The formula for difference of squares

`a^2 - b^2 =(a+b)(a-b)`

(–7x + 4)(–7x + 4) both parenthesis having same terms so this will not result in difference of squares

(–7x + 4)(4 – 7x) both parenthesis having same terms so this will not result in difference of squares

(–7x + 4)(–7x – 4) Sign changes in the middle of both parenthesis , so this will result in difference of squares

(–7x + 4)(7x – 4) sign changes for both terms in both parenthesis so this will not result in difference of squares