Question 823405
Since area = L * W
  x^3 -2x^2 -5x+6 = ( x-3 )( W )
and
  W = {{{(x^3 -2x^2 -5x+6) / ( x-3 )}}}
Here is the long division.

      
_________{{{x^2+x-2}}}
(x-3)|{{{x^3 -2x^2 -5x+6 }}}
_____{{{x^3-3x^2}}}
________{{{x^2-5x}}}
________{{{x^2-3x}}}
___________{{{-2x+6}}}
___________{{{-2x+6}}}
________________0

So the width is {{{x^2+x-2}}}.