Question

a) x+5/7 = 10/-35

b) 2/x = x/8

c) x-3/2 = 32/x-3

Answer 1

\(a,x+\dfrac{5}{7}=\dfrac{10}{-35}\\ x=\dfrac{-10}{35}-\dfrac{5}{7}\\ x=-1\\ b,\dfrac{2}{x}=\dfrac{x}{8}\\ x.x=2.8\\ x^2=16\\ x=\pm4\)

Answer 2

a, \(x\) + \(\dfrac{5}{7}\) = \(\dfrac{10}{-35}\)

   \(x\)         = \(-\dfrac{10}{35}\) - \(\dfrac{5}{7}\)

    \(x\)        = -1

b, \(\dfrac{2}{x}\)     =   \(\dfrac{x}{8}\)

     \(x^2\)   = 16

     \(\left[{}\begin{matrix}x=-4\\x=4\end{matrix}\right.\)

Vậy \(x\) \(\in\){ -4; 4}

c, \(\dfrac{x-3}{2}\) = \(\dfrac{32}{x-3}\)

   (\(x-3\))(\(x-3\)) = 32\(\times\) 2

  (\(x-3\))(\(x\) - 3) = 64

 (\(x-3\))²         = 8²

 \(\left[{}\begin{matrix}x-3=-8\\x-3=8\end{matrix}\right.\)

\(\left[{}\begin{matrix}x=-8+3\\x=8+3\end{matrix}\right.\)

\(\left[{}\begin{matrix}x=-5\\x=11\end{matrix}\right.\)

Vậy \(x\) \(\in\) { -5; 11}