Question

Answer 1

Bài 2

a,\(\dfrac{2}{3}\)x-\(\dfrac{1}{3}\)=\(\dfrac{1}{2}\)-\(\dfrac{2}{3}\)

\(\dfrac{2}{3}\)x-\(\dfrac{1}{3}\)=\(\dfrac{-1}{6}\)

\(\dfrac{2}{3}\)x=\(\dfrac{-1}{6}\)+\(\dfrac{1}{3}\)

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

x=\(\dfrac{1}{6}\):\(\dfrac{2}{3}\)

x=\(\dfrac{1}{4}\)

b,\(\dfrac{3}{x+5}\)=\(\dfrac{3}{20}\)

⇒x+5=20

x=20-5

x=15

Answer 2

Giải:

a) \(\dfrac{1}{2}-\left(\dfrac{2}{3}x-\dfrac{1}{3}\right)=\dfrac{2}{3}\) 

                 \(\dfrac{2}{3}x-\dfrac{1}{3}=\dfrac{1}{2}-\dfrac{2}{3}\) 

                 \(\dfrac{2}{3}x-\dfrac{1}{3}=\dfrac{-1}{6}\) 

                        \(\dfrac{2}{3}x=\dfrac{-1}{6}+\dfrac{1}{3}\) 

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

                           \(x=\dfrac{1}{6}:\dfrac{2}{3}\)  

                           \(x=\dfrac{1}{4}\) 

b) \(\dfrac{3}{x+5}=15\%\) 

    \(\dfrac{3}{x+5}=\dfrac{3}{20}\) 

\(\Rightarrow x+5=20\) 

           \(x=20-5\) 

           \(x=15\) 

Chúc bạn học tốt!

Answer 3

Bài 2:

a) \(\dfrac{1}{2}\)-\(\left(\dfrac{2}{3}x-\dfrac{1}{3}\right)\)=\(\dfrac{2}{3}\)

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

        \(\left(\dfrac{2}{3}x-\dfrac{1}{3}\right)\)=\(\dfrac{-1}{6}\)

        \(\dfrac{2}{3}x\)             = \(\dfrac{-1}{6}\)+\(\dfrac{1}{3}\)

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

           \(x\)              = \(\dfrac{1}{6}\):\(\dfrac{2}{3}\)

          \(x\)               = \(\dfrac{1}{4}\)

b) 

\(\dfrac{3}{x+5}\)=\(\dfrac{3}{20}\)

⇒x+5=20

x=20-5

x=15