# Factor this unless it is fully factored?

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#18rs^2 - 2r#

##### 2 Answers

Apr 30, 2018

#### Explanation:

Apr 30, 2018

#### Explanation:

Given:

#18rs^2-2r#

Note that both terms are divisible by

#18rs^2-2r = 2r(9s^2-1)#

Note that both

So we can use the difference of squares identity:

#A^2-B^2=(A-B)(A+B)#

with

#9s^2-1 = (3s)^2-1^2 = (3s-1)(3s+1)#

Putting it all together:

#18rs^2-2r = 2r(3s-1)(3s+1)#