I. $frac{7}{{sqrt x }} + frac{5}{{sqrt x }} = sqrt x$

II. ${y^2} - frac{{{{(12)}^{frac{5}{2}}}}}{{sqrt y }} = 0$

$frac{7}{{sqrt x }} + frac{5}{{sqrt x }} = sqrt x$

(i) 12 = x

(ii) ${y^2} - frac{{{{(12)}^{frac{5}{2}}}}}{{sqrt y }} = 0$

${y^{frac{5}{2}}} = {(12)^{frac{5}{2}}},y = 12$

Hence x = y