Tìm x: a) \(\Large\dfrac {1}{3} +\dfrac{x}{3}\times\dfrac{1}{6}=\dfrac

Tìm x:

a) \(\Large\dfrac {1}{3} +\dfrac{x}{3}\times\dfrac{1}{6}=\dfrac{7}{18}.\)

b) \(\Large\dfrac{4}{7}:x\times\dfrac{3}{2}+\dfrac{1}{7}=\dfrac{13}{7}.\) 

(Viết đáp án dưới dạng số thập phân).

 

• A. 1
• B. 0,5

Hướng dẫn:

a) \(\Large\dfrac{1}{3} +\dfrac{x}{3}\times\dfrac{1}{6}=\dfrac{7}{18}\)

 \(\Large\dfrac{x}{3} \times \dfrac{1}{6} = \dfrac{7}{{18}} - \dfrac{1}{3}\)

\(\Large\dfrac{x}{3} \times \dfrac{1}{6} = \dfrac{1}{{18}}\)

\(\Large\dfrac{x}{3} = \dfrac{1}{{18}}:\dfrac{1}{6}\)

\(\Large\dfrac{x}{3} = \dfrac{1}{3} \Rightarrow x = 1\)     

b) \(\Large \dfrac{4}{7}:x\times\dfrac{3}{2}+\dfrac{1}{7}=\dfrac{13}{7}\)

    \(\Large\dfrac{4}{7}:x\times\dfrac{3}{2}=\dfrac{12}{7}\)

    \(\Large\dfrac{4}{7}:x=\dfrac{8}{7}\)

    \(\Large x=0,5\)

Đáp số: a) 6.

             b) 0,5.