Question 723990

{{{ (x^3 - x^2 - 12x) / (x^3 - 9x)}}}

{{{ x(x^2 - x - 12) / x(x^2 - 9)}}}

{{{ cross(x)(x^2 - x - 12) /cross( x)(x^2 - 9)}}}


now factor {{{ (x^2 - x - 12)}}}...replace {{{-x}}} with {{{3x-4x}}}

{{{(x^2+3x-4x-12)}}}...group

{{{((x^2+3x)-(4x+12))}}}

{{{(x(x+3)-4(x+3))}}}

{{{(x-4)(x+3)}}}

and

write {{{(x^2 - 9)}}} as {{{(x - 3)(x+3)}}}


plug both in your expression


{{{ ((x-4)(x+3)) / ((x - 3)(x+3))}}}


{{{ ((x-4)cross((x+3))) / ((x - 3)cross((x+3)))}}}


{{{ (x-4) / (x - 3)}}}