Question

(x + 3) . (x - 3)
(a + 1) . (a - 1)
(5 + y) . ( 5 - y)

Answer 1

(x + 3) . (x - 3) = x² - 3² = x² - 9

(a + 1) . (a - 1)= a² - 1² = a² - 1

(5 + y) . ( 5 - y)= 5² - y² = 25 - y²