tìm x b. 0,(3) + 0, (384615) + 3/15 . x / 0,0(3) + 13 = 50/85

$\frac{0,(3)+0,(384615)+\frac{3}{15}.x}{0,0(3)+13}=$$\frac{50}{85}$
$\frac{\frac{28}{39}+\frac{3}{13}.x}{\frac{391}{30}}=\frac{10}{17}$

$x.\frac{3}{13}+\frac{28}{39}=$ $\frac{23}{3}$

$x.\frac{3}{13}=$ $\frac{23}{3}-$ $\frac{28}{39}$

$x.\frac{3}{13}=$ $\frac{271}{39}$

$x=\frac{271}{39}:$ $\frac{3}{13}$

$x=\frac{271}{39}.\frac{13}{3}$

$x=\frac{271}{9}$

vậy $x=\frac{271}{9}$