Đáp án:
Giải thích các bước giải:
bài 1
$a) = \dfrac{2. (-1). 13. 3. 3. 2. 5}{3. (-1). 2. 2. (-1). 5. 2. 13}= -3$
$b) = \dfrac{15. (8+ 4)}{12. 3}= \dfrac{15. 12}{12. 3}= 5$
Bài 2:
$a) \dfrac{10}{3}. x+ \dfrac{67}{4}= \dfrac{53}{4}$
$\dfrac{10}{3}. x= \dfrac{53}{4}-\dfrac{67}{4}$
$\dfrac{10}{3}. x= \dfrac{7}{2}$
$x= \dfrac{7}{2}: \dfrac{10}{3}$
$x= \dfrac{21}{20}$
$b) \dfrac{x}{3}= \dfrac{-1}{7}+ \dfrac{10}{21}$
$\dfrac{x}{3}= \dfrac{1}{3}$
$x= \dfrac{1. 3}{3}= 1$
$c) x- \dfrac{1}{4}. x= \dfrac{1}{2}$
$x. (1- \dfrac{1}{4})= \dfrac{1}{2}$
$x. \dfrac{3}{4}= \dfrac{1}{2}$
$x= \dfrac{1}{2}: x. \dfrac{3}{4}$
$x= \dfrac{2}{3}$
$d) \dfrac{-5}{6}+ \dfrac{16}{6}+ \dfrac{-29}{6}≤ x≤ \dfrac{-1}{2}+ \dfrac{4}{2}+ \dfrac{5}{2}$
$\dfrac{-18}{6}≤ x≤ \dfrac{8}{2}$
$-3≤ x≤ 4$
$⇒ x∈ {± 3; ± 2; ± 1; 0; 4}$
