Đáp án:
Giải thích các bước giải:
$1) x= \dfrac{4}{5}- \dfrac{2}{3}$
$x= \dfrac{2}{15}$
$2) x= \dfrac{7}{21}+ \dfrac{2}{7}$
$x= \dfrac{7}{21}+ \dfrac{6}{21}$
$x= \dfrac{13}{21}$
$3) -x= \dfrac{-8}{11}+ \dfrac{3}{4}$
$-x= \dfrac{1}{44}$
$⇒ x= -\dfrac{1}{44}$
$4) \dfrac{11}{12}- \dfrac{2}{5}- x= \dfrac{2}{3}$
$-x= \dfrac{2}{3}- \dfrac{11}{12}+ \dfrac{2}{5}$
$-x= \dfrac{3}{20}$
$⇒ x= -\dfrac{3}{20}$
$5) \dfrac{1}{2}- \dfrac{13}{12}≤ x≤ \dfrac{1}{24}- \dfrac{-5}{24}$
$\dfrac{-7}{12}≤ x≤ \dfrac{1}{24}$
$⇒ \dfrac{-14}{24}≤ x≤ \dfrac{1}{24}$
$⇒ x∈ \dfrac{-14}{24}; \dfrac{-13}{24}; \dfrac{-12}{24};....; \dfrac{1}{24}$
