Question 472967
{{{(x^2-81)/(x+9)}}}



{{{((x-9)(x+9))/(x+9)}}}



{{{((x-9)*highlight((x+9)))/highlight((x+9))}}}



{{{((x-9)*cross((x+9)))/cross((x+9))}}}



{{{x-9}}}



So {{{(x^2-81)/(x+9)=x-9}}} where {{{x<>-9}}}