Simplify:

$\displaystyle \frac{{\left({x}^{{-{7}}}{y}^{{-{7}/{6}}}\right)}^{{{2}}}}{{{x}^{{-{3}/{4}}}{y}^{{-{1}/{4}}}}}$

Entry Tip: put the numerator and denominator in parenthesis. Also put the exponents in parenthesis. To type $\displaystyle \frac{{a}^{{\frac{{1}}{{2}}}}}{{b}^{{\frac{{2}}{{3}}}}}$ type (a)^(1/2)/(b^(2/3)). Be sure to use the preview button and be sure you like the format before you hit submit!