1/
$\dfrac{1}{4}+x=\dfrac{5}{2}×\dfrac{8}{7}$
$\dfrac{1}{4}+x=\dfrac{20}{7}$
$x=\dfrac{20}{7}-\dfrac{1}{4}$
$x=\dfrac{73}{28}$
2/
$\dfrac{7}{3}-x=\dfrac{11}{5}×\dfrac{5}{6}$
$\dfrac{7}{3}-x=\dfrac{11}{6}$
$x=\dfrac{7}{3}-\dfrac{11}{6}$
$x=\dfrac{1}{2}$
chúc bạn học tốt!