Cái này bn lầy máy tính ra tính tí là xong thôi

1,\(\dfrac{1}{7}=\dfrac{8}{-x}\Leftrightarrow-x=56\Leftrightarrow x=-56\)

2,\(\dfrac{3x}{9}=\dfrac{2}{6}\Leftrightarrow\dfrac{x}{3}=\dfrac{1}{3}\Leftrightarrow x=1\)

3,\(4\dfrac{2}{5}:\left(\dfrac{-33}{10}\right)+x=-1\dfrac{5}{6}\Leftrightarrow\dfrac{22}{5}:\left(\dfrac{-33}{10}\right)+x=\dfrac{-11}{6}\Leftrightarrow\dfrac{-4}{3}+x=\dfrac{-11}{6}\Leftrightarrow x=\dfrac{-1}{2}\\ \\ \\ \\ \\ \\ \\ 4,45\%.x-2\dfrac{3}{8}=-1\dfrac{31}{40}\Leftrightarrow45\%.x-\dfrac{19}{8}=\dfrac{-71}{40}\Leftrightarrow45\%.x=\dfrac{3}{5}\Leftrightarrow x=\dfrac{1}{75}\)

My hero in my mind is my sister.She is very kind and happy. She is very pretty. She helped me several time when i disappointed. she encourged me very much and i become very happy again. she is not good at Maths but she goods at English so she help me so much.That's my hero-sister

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len google ma dich