Question 746091
231=7(x+8)x

the 231 seems large, so we look for a way to simplify - and it turns out to be a multiple of 7:


{{{7*33=7*(x+8)x}}}


using cancellation and rearranging terms we get the following:

{{{x^2+8x=33}}}


{{{x^2+8x-33=0}}}


Notice that 11+(-3)=8 and (11)(-3)=-33 so we'll use them in our grouping:


{{{x^3+11x-3x-33=0}}}



{{{x(x+11)-3(x+11)=0}}}


{{{(x-3)(x+11)=0}}}


which has solutions


x=3  and x=-11


:)