Find x if ^n P_r=x^n C_r. - Vidyadip

Question

Find $x$ if ${ }^n P_r=x^n C_r$.

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Answer

$\begin{aligned}{ }^n P_r & =x\left({ }^n C_r\right) \\ x & =\frac{{ }^n P_r}{{ }^n C_r} \\ & =\frac{\frac{n !}{(n-r) !}}{n !} \\ & =r !\end{aligned}$

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