Question

1 Tìm​ x biết:

a)\(\dfrac{1}{3}\)x+\(\dfrac{2}{5}\)(x+1)=0 b)20%x+\(\dfrac{2}{5}\)x=x-4

Answer 1

a, \(\dfrac{1}{3}x+\dfrac{2}{5}\left(x+1\right)=0\)

\(\Rightarrow\dfrac{1}{3}x+\dfrac{2}{5}x+\dfrac{2}{5}=0\)

\(\Rightarrow\left(\dfrac{1}{3}+\dfrac{2}{5}\right)x=\dfrac{-2}{5}\)

\(\Rightarrow\dfrac{11}{15}x=\dfrac{-2}{5}\)

\(\Rightarrow x=\dfrac{-6}{11}\)

Answer 2

Mình làm phần b nhé!

b) \(20\%x+\dfrac{2}{5}x=x-4\)

\(\Leftrightarrow20\%x+\dfrac{2}{5}x-x=-4\)

\(\Leftrightarrow x\left(20\%+\dfrac{2}{5}-1\right)=-4\)

\(\Leftrightarrow x\left(-\dfrac{2}{5}\right)=-4\)

\(\Leftrightarrow x=-4:\dfrac{-2}{5}\)

\(\Leftrightarrow x=10\)

Chúc bạn học tốt!