Answer:
(11 - a)(7 + a)
Step-by-step explanation:
81 - (a - 2)² ← is a difference of squares and factorises in general as
a² - b² = (a - b)(a + b) , then
81 - (a - 2)²
= 9² - (a - 2)²
= (9 - (a - 2) )(9 + (a - 2) )
= (9 - a + 2)(9 + a - 2)
= (11 - a)(7 + a)
