Answer
$ P(x)=\dfrac{2x^2+2000}{x}$
Work Step by Step
Consider $ x $ and $ y $ to be the width and height.
Thus, $ Area = width \times height=xy $
so, $ y= \dfrac{1000}{x}$
This implies that $ P(x)=2x+\dfrac{2000}{x}=\dfrac{2x^2+2000}{x}$
Therefore, $ P(x)=\dfrac{2x^2+2000}{x}$