Which will result in a difference of squares?
A. (–7x + 4)(–7x + 4)
B. (–7x + 4)(4 – 7x)
C. (–7x + 4)(–7x – 4)
D. (–7x + 4)(7x – 4)
A difference in squares is given by (a^2-b^2), every problem that can be factored as the equation is a difference of squares problem, so one need to find which numbers squares, (a-b)(a+b) or (a+b)(a-b) thus the equation C,
Thus, the problem has taken the factored out square shown.