Answer
$\displaystyle \frac{6(x+2)}{x^{3/4}}$
Work Step by Step
$[x^{1/4}=x^{1-3/4}=x\cdot x^{-3/4}]$
$ 12x^{-3/4}+6x^{1/4}=6\cdot 2x^{-3/4}+6x\cdot x^{-3/4}\qquad$... factor out $6x^{-3/4}$
$=6x^{-3/4}(2+x)\qquad $... $a^{-n}=\displaystyle \frac{1}{a^{n}}$
= $\displaystyle \frac{6(x+2)}{x^{3/4}}$
