Question

Tìm x

3/7 - 2/5 = x/70

 

Answer 1

   \(\dfrac{3}{7}-\dfrac{2}{5}=\dfrac{x}{70}\)

=> \(\dfrac{1}{35}=\dfrac{x}{40}\) 

=> \(40=35\times x\) 

=> \(x=40\div35\) 

=> \(x=\dfrac{8}{7}\)

Answer 2

\(\dfrac{3}{7}-\dfrac{2}{5}=\dfrac{x}{70}\)

\(\dfrac{15}{35}-\dfrac{14}{35}=\dfrac{x}{70}\)

\(\dfrac{1}{35}=\dfrac{x}{70}\)

\(\dfrac{2}{70}=\dfrac{x}{70}\)

\(x=2\)

Answer 3

\(\dfrac{3}{7}-\dfrac{2}{5}=\dfrac{x}{70}\)

\(\dfrac{3}{7}=\dfrac{x}{70}+\dfrac{2}{5}\)

\(\dfrac{3}{7}=\dfrac{x+28}{70}\)

\(\dfrac{30}{70}=\dfrac{x+28}{70}\)

\(x+28=30\)

       \(x=30-28\)

       \(x=2\)