How do you complete the square to solve #x^2 - 2x - 35 = 0#?

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Answer 1 · 2015-05-25T15:46:27

#0 = x^2-2x-35#

#= x^2-2x+1-1-35#

#=(x-1)^2-36#

#= (x-1)^2-6^2#

#= ((x-1)-6)((x-1)+6)#

#= (x-7)(x+5)#

So #x=7# or #x=-5#

I used the difference of squares inequality along the way:

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