Question
If $\frac{\text{x}}{\text{x}^{1.5}}=8\text{x}^{-1}$ then x =
  1. $\frac{\sqrt{2}}{4}$
  2. $\sqrt[2]{2}$
  3. $4$
  4. $64$

Answer

  1.  $64$
Solution:
For $\frac{\text{x}}{\text{x}^{1.5}}=8\text{x}^{-1}$ we have to find the value of x.
So,
$\frac{\text{x}^1}{\text{x}^{1.5}}=8\text{x}^{-1}$
$\text{x}^{1-1.5}8\text{x}^{-1}$
$\text{x}^{-0.5}=2^3\text{x}^{-1}$
$\frac{\text{x}^{0.5}}{\text{x}^{-1}}=2^3$
$\frac{\text{x}^{-\frac{5}{10}}}{\text{x}^{-1}}=2^3$
$\text{x}^{-\frac{1}{2}+1}=2^3$
$\text{x}^{\frac{1}{2}+\frac{2}{2}}=2^3$
$\text{x}^{\frac{-1+2}{2}}=2^3$
$\text{x}^{\frac{1}{2}}=2^3$
By raising both sides to the power 2 we get
$\text{x}^{\frac{1}{2}\times2}=2^{3\times2}$
$\text{x}^{\frac{1}{2}\times2}=2^6$
$\text{x}^1=64$
The value of x is 64
Hence the correct alternative is d. 

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