Question

Factor completely.

5x^2 - 45
Select one of the options below as your answer:
A. 5(x + 3)(x - 3)
B. 5(x^2 - 45)
C. 5(x - 9)(x + 9)
D. (5x + 9)(x - 5)

Answer 1

5x^2 - 45

5(x^2 - 9)

what's the next step?

Answer 2

would use the distributive property

Answer 3

no, you would use the difference of squares rule

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

Answer 4

x^2 - 9

x^2 - 3^2

(x-3)(x+3)

Answer 5

So 5(x^2 - 9) turns into 5(x-3)(x+3)

Answer 6

thank you.. how do u know all this stuff

Answer 7

lots and lots of practice

Answer 8

so just keep practicing and it will click better

Answer 9

hopefully

Answer 10

just keep at it and don't give up

Answer 11

i will try

Answer 12

alright great