Question

Which polynomial identity will prove that 49-4=45

Answer 1

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.