Đáp án:
a) $\dfrac{4}{21}$
b) ${0, 1, 2, 3}$
c) $30$
Giải thích các bước giải:
a)
$\dfrac{3}{8}.(x - \dfrac{2}{3}) - \dfrac{2}{9}.(3x - \dfrac{1}{2})=\dfrac{-7}{36}$
$\dfrac{3}{8}x - \dfrac{1}{4} - \dfrac{2}{3}x + \dfrac{1}{9} = \dfrac{-7}{36}$
$\dfrac{3}{8}x - \dfrac{2}{3}x - \dfrac{1}{4} + \dfrac{1}{9} = \dfrac{-7}{36}$
$\dfrac{-7}{24}x - \dfrac{1}{4} + \dfrac{1}{9} = \dfrac{-7}{36}$
$\dfrac{-7}{24}x - \dfrac{1}{4} = \dfrac{-7}{36} - \dfrac{1}{9}$
$\dfrac{-7}{24}x - \dfrac{1}{4} = \dfrac{-7}{36} - \dfrac{4}{36}$
$\dfrac{-7}{24}x - \dfrac{1}{4} = \dfrac{-11}{36}$
$\dfrac{-7}{24}x = \dfrac{-11}{36} + \dfrac{1}{4}$
$\dfrac{-7}{24}x = \dfrac{-11}{36} + \dfrac{9}{36}$
$\dfrac{-7}{24}x = \dfrac{-1}{18}$
$x = \dfrac{-1}{18} : \dfrac{-7}{24}$
$x = \dfrac{-1}{18} . \dfrac{-24}{7}$
$x = \dfrac{4}{21}$
b)
$0,6 - 160$% $< x \leq \dfrac{11}{3} : \dfrac{22}{18}$
$\dfrac{3}{5} - \dfrac{8}{5} < x \leq \dfrac{11}{3} . \dfrac{9}{11}$
$-1 < x \leq 3$
$=> x ∈ {0, 1, 2, 3}$
c)
$50$%$x + \dfrac{2}{3}x = x - 5$
$\dfrac{1}{2}x + \dfrac{2}{3}x = x - 5$
$x(\dfrac{1}{2} + \dfrac{2}{3}) = x - 5$
$\dfrac{7}{6}x = x - 5$
$\dfrac{7}{6}x - x = 5$
$\dfrac{1}{6}x = 5$
$x=5 : \dfrac{1}{6}$
$x=30$
#Ryanbui12
