How do you use the difference of two squares formula to factor #x^2-4#?

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Answer 1 · 2015-05-04T22:16:30

Factor #x^2-4# using the difference of two squares.

General formula: #(a^2-b^2)=(a-b)(a+b)#

#(x^2-4)=(x^2-2^2)=(x-2)(x+2)#

Answer 2 · 2015-05-04T22:18:21

So the difference of 2 squares formula says that #(a+b)(a-b)=a^2 -b^2#

In this case, #a=sqrt(1)# and #b= sqrt(4)# (we get this from #x^2-4#)

So, #a=1# and #b=±2#

Therefore, #x^2-4=(x+2)(x-2)#