Question 76483
{{{ x^3 + ax + 3a + 3x^2 }}}
factor an x out of the first pair and a 3 out of the second pair
{{{ x(x^2+a) +3(a+x^2) }}}
x^2+a is the same thing as a+x^2 ... rewrite it as such
{{{ x(x^2+a) +3(x^2+a) }}}
factor out x^2+a
{{{ (x^2+a)(x+3) }}}
Done