X2-81 Factor each polynomial

Step-by-step explanation:

Recall that the "difference of two squares" occurs frequently and that there is a formula for factoring it:

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

Therefore,

x^2 - 81 = (x - 9) (x + 9).

x2 is incorrect; write x^2 or x² in its place.