Answer
$x=\frac{3}{5}$
Work Step by Step
We set up a proportion, using $\frac{x_1}{y_1}=\frac{x_2}{y_2}$, where $x_1$ and $y_1$ represent the $x$ and $y$ values in the problem, and $x_2$ and $y_2$ represent the new values.
In this case, we don't know what $x_2$ is, so we will represent that as $x$.
We set up the proportion to get
$\frac{-3}{5}=\frac{x}{-1}$
Cross multiplying gives
$5x=3$
To isolate $x$, we divide both sides by 5, giving
$x=\frac{3}{5}$