Question

What is the factored form of the expression?
s^2 - 81

Answer 1

\[s ^{2} - 81\]

Answer 2

Difference of two perfect squares:
(x-a)(x+a)=x^2-a^2

Answer 3

\[(a-b)(a+b)=a^2+ab-ba-b^2=(a^2-b^2)\]

Answer 4

(s-9)(s+9)

Answer 5

So what do use for x and a @Luigi0210
the answer choices are:
a. (s-9)(s-9)
b. (s-9)(s+11)
c.(s-9)(s+9)
d.(s+9) (s+9)
I am learning toward D and I'm pretty sure it's not b

Answer 6

x represents your variable a is your number

Answer 7

what two numbers multiply to 81?

Answer 8

its C

Answer 9

9 and 9 that's why I was thinking definitely not b

Answer 10

factor (s-9)(s+9)
s^2 +9s-9s-81 (factor)
s^2 -81 (simplify)

Answer 11

Thanks

Answer 12

Yup :P
Now, they need to have opposite signs so they can cancel out like drotz showed

Answer 13

yeah so you guys should check out my question... its a brain stomper

Answer 14

link?

Answer 15

http://openstudy.com/study#/updates/51aecad5e4b06ee3ee265fd2

i think that will work i hope