Consider the polynomial identity (difference of squares):
(x+y)(x-y) = x² - y²
Set x =7 and y = 2 to obtain
(7+2)*(7-2) = 7² - 2²
9*5 = 49 - 4
45 = 49 - 4
This is the result required, obtained by using difference of squares.
Answer: Difference of squares.
