Question

[dothithuuyen]

Tim x, biết;

   a, \(\frac{x}{4}=\frac{9}{10}\)

   b, \(\frac{x}{24}=\frac{6}{x}\)

  c, \(\frac{5-2x}{4x-\frac{1}{-5}}\)

  d, \(\frac{10-2x}{6}=\frac{27}{5-x}\)

   HELP ME!!!!!!!!!!!!!!!!!!!

Answer 1

[Nguyễn Linh Chi]

   a, \(\frac{x}{4}=\frac{9}{10}\)

       \(x.10=4.9\)

       \(x.10=36\)

       \(x=36:10=3,6\)

   b, \(\frac{x}{24}=\frac{6}{x}\)

       \(x.x=6.24\)

       \(x^2=144=12^2\)

       \(x=\pm12\)

  c, \(\frac{5-2x}{4x-\frac{1}{-5}}\)

    Thiếu đề.

  d, \(\frac{10-2x}{6}=\frac{27}{5-x}\)

       \(\frac{2\left(5-x\right)}{6}=\frac{27}{5-x}\)

      \(\frac{5-x}{3}=\frac{27}{5-x}\)

     \(\left(5-x\right)\left(5-x\right)=27.3\)

     \(\left(5-x\right)^2=9^2\)

       5 - x =9 hoặc  5 - x = -9 

       x = 5-9    hoặc x = 5+9

       x= -4 hoặc x = 14

Answer 2

[Bùi Anh Tuấn]

\(\frac{x}{4}=\frac{9}{10}\)

\(\Rightarrow10x=4\cdot9\)

\(\Rightarrow10x=36\)

\(\Rightarrow x=\frac{36}{10}=\frac{18}{5}\)

\(b,\frac{x}{24}=\frac{5}{x}\)

\(\Rightarrow x\cdot x=24\cdot5\)

\(\Rightarrow x^2=100\)

\(\Rightarrow x=\pm10\)