Đáp án:

Giải thích các bước giải:

 b)

$-\dfrac{15}{12}x + \dfrac{3}{7} = \dfrac{6}{5}x - \dfrac{1}{2}$

$\Leftrightarrow -\dfrac{15}{12}x - \dfrac{6}{5}x = -\dfrac{1}{2} - \dfrac{3}{7}$

$\Leftrightarrow \left(-\dfrac{25}{20} - \dfrac{24}{20}\right)x = -\dfrac{7 + 6}{14}$

$\Leftrightarrow -\dfrac{49}{20}x = -\dfrac{13}{14}$

$\Leftrightarrow x = \dfrac{-13}{14} \cdot \left(-\dfrac{20}{49}\right) = \dfrac{260}{686} = \dfrac{130}{343}$

Vậy $x = \dfrac{130}{343}$

`c)` 

$-\dfrac{6}{x} = \dfrac{9}{-15}$

$\Leftrightarrow -\dfrac{6}{x} = -\dfrac{3}{5}$

$\Leftrightarrow \dfrac{6}{x} = \dfrac{3}{5}$

$\Leftrightarrow x = \dfrac{6 \cdot 5}{3} = 10$ (tm x khác 0)

Vậy $x = 10$

d)

$\dfrac{2}{9} = \dfrac{x}{27}$

$\Leftrightarrow x = \dfrac{2 \cdot 27}{9} = 6$

Vậy $x = 6$