Question

NEED HELP ASAP!!!! 15POINTS!

Answer 1

Answer:

(k +9)(k - 9)

Step-by-step explanation:

a² - b² = (a + b)(a -b)

k² - 81 = k² - 9²

           = (k +9)(k - 9)

Answer 2

It’s (k-9)(k+9) because when expanded you get k^2 +9k -9k -81 which simplifies to = k^2-81. a good trick with questions like this is square root the second number which in this instance is 9 and you will have a plus bracket and a minus bracket. (k+9)(k-9)