If the coefficients of the equation whose roots are $k$ times the roots of the equation, $x^3+\frac{1}{4}…

If the coefficients of the equation whose roots are $k$ times the roots of the equation, $x^3+\frac{1}{4} x^2-\frac{1}{16} x+\frac{1}{144}=0$ are integers, then a possible value of $k$ is
  1. $3$
  2. $12$
  3. $9$
  4. $4$

Solution

Given equation,
The equation whose roots are $\mathrm{k}$ times the roots of the eq. (i), is $\begin{aligned} & \left(\frac{x}{k}\right)^3+\frac{1}{4}\left(\frac{x}{k}\right)^3-\frac{1}{16}\left(\frac{x}{k}\right)+\frac{1}{144}=0 \\ & \Rightarrow x^3+\frac{k}{4} x^2-\frac{k^2}{16} x+\frac{k^3}{144}=0 \end{aligned}$ Also given that, coefficients of the above equation are integer. $k=12$

Asked in: AP EAMCET 2016

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