How do you factor #81x^2 - 36y^2?

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Answer 1 · 2015-06-21T03:53:22

The answer is #9(3x+2y)(3x-2y)#.

Factor #81x^2-36y^2#.

Factor out #9#.

#9(9x^2-4y^2)#

#(9x^2-4y^2)# is in the form the difference of squares:

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

#a=3x;##b=2y#

#9((3x)^2-(2y)^2)# =

#9(3x+2y)(3x-2y)#