d) Ta có
$VT = \dfrac{xyz-yzt}{y^2 z^2 - yz} = \dfrac{yz(x-t)}{yz(yz -1)} = \dfrac{x-t}{yz-1} = \dfrac{t-x}{1-yz} = VP$.
e) Ta có
$VT = \dfrac{\frac{4}{11} - \frac{12}{31}+ \frac{16}{59}}{\frac{3}{11} - \frac{9}{31}+ \frac{12}{59}} = \dfrac{4 \left( \frac{1}{11} - \frac{3}{31}+ \frac{4}{59} \right)}{3 \left( \frac{1}{11} - \frac{3}{31}+ \frac{4}{59} \right)} = \dfrac{4}{3} = VP$.
