Tìm x: a) \(\Large x+\dfrac{5}{7}=\dfrac{13}{2}\) b) \(\Large x\times\

Tìm x:

a) \(\Large x+\dfrac{5}{7}=\dfrac{13}{2}\)

b) \(\Large x\times\dfrac{1}{4}\times\dfrac{1}{3}=\dfrac{7}{8}\)

c) \(\Large\dfrac{12}{5}-x=\dfrac{8}{11}\)

(Viết đáp án dưới dạng phân số tối giản a/b).

• A. a) x= 81/14
• B. b) x= 21/2
• C. c) x= 92/55

Hướng dẫn:

a) \(\Large x+{5\over7}={13\over2}\)

    \(\Large x={13\over2}-{5\over7}\)

    \(\Large x={91-10\over14}={81\over14}\)

Vậy \(\Large x={81\over14}\).

b) \(\Large x\times{1\over4}\times{1\over3}={7\over8}\)

   \(\Large x={7\over8} :{1\over3} : {1\over4}\)

   \(\Large x={21\over2}\)

Vậy \(\Large x={21\over2}\).

c) \(\Large {12\over5}-x={8\over11}\)

  \(\Large x= {12\over5} - {8\over11}\)

  \(\Large x={92\over55}\)

Vậy \(\Large x={92\over55}\).