Answer
Let us consider difference of two squares $a^{2}$ - $b^{2}$.
Let $a^{2}$ - $b^{2}$ = 0.
if $a^{2}$ = $b^{2}$ then a = b or -b and b = a or -a.
So $a^{2}$ - $b^{2}$ = (a + b) (a - b)
Work Step by Step
For example let us take polynomial $a^{2}$ - $b^{2}$.
Let $a^{2}$ - $b^{2}$ = 0.
if $a^{2}$ = $b^{2}$ then a = b or -b and b = a or -a
So $a^{2}$ - $b^{2}$ = (a + b) (a - b)
Example-
25$x^{2}$ - 81 = $5^{2}$$x^{2}$ - $9^{2}$ = (5x + 9)(5x - 9)
