#### Answer

Fill the blank with
$0.85x$

#### Work Step by Step

If the original price is x, we can say that
($ 100\%$ of the price) is x.
A reduction of 15$\%$ means that I pay $ 100\%-15\%=85\%$ of the full price.
$85\displaystyle \%=\frac{85}{100}=0.85.$
"(fraction) of (quantity)" is written as
(fraction) $\times$ (quantity).
So, the price I pay is
$(0.85)$ of (x)
or
$0.85x$.
Fill the blank with
$0.85x$