Question

giúp mik với ạ. cảm ơn ạ

Answer 1

3: \(\Leftrightarrow x\cdot\dfrac{-3}{5}=\dfrac{1}{4}+\dfrac{3}{4}=1\)

nên x=-5/3

4: \(\Leftrightarrow x\cdot\dfrac{4}{28}=\dfrac{28}{3}\cdot\dfrac{3}{28}=1\)

hay x=28/4=7

5: \(\Leftrightarrow x:\left(\dfrac{7}{2}-\dfrac{31}{6}\right)=\dfrac{21}{5}-\dfrac{20}{3}\)

\(\Leftrightarrow x:\dfrac{-5}{3}=\dfrac{-37}{15}\)

\(\Leftrightarrow x=\dfrac{37}{15}\cdot\dfrac{5}{3}=\dfrac{37}{9}\)