How do you factor #x^2 +8x -24#?

1 Answer
George C.
Aug 28, 2016

#x^2+8x-24=(x+4-2sqrt(10))(x+4+2sqrt(10))#

Explanation:

The difference of squares identity can be written:

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

Use this with #a=(x+4)# and #b=2sqrt(10)# as follows:

#x^2+8x-24#

#=x^2+8x+16-40#

#=(x+4)^2-(2sqrt(10))^2#

#=((x+4)-2sqrt(10))((x+4)+2sqrt(10))#

#=(x+4-2sqrt(10))(x+4+2sqrt(10))#

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