Answer
$x=\dfrac{5200}{180}=\dfrac{260}{9}=28.89$ (approximate value)
Work Step by Step
Given that $\dfrac{80x}{100}+x=52$
We will have to isolate $x$. In order to this take whole terms other side to get the value of $x$.
$100(\dfrac{80x}{100})+100x=5200$
or, $80x+100x=5200$
or, $180x=5200$
or, $x=\dfrac{5200}{180}=\dfrac{260}{9}=28.89$ (approximate value)