Answer
$1$
Work Step by Step
In order for two non-vertical lines to be parallel, they must have the same slope. Therefore, to find the slope of a line parallel to this one, we must identify the slope of this one.
The slope-intercept form of a linear equation of a non vertical line is $y=mx+b$, where $m$ is the slope and $b$ is the $y$-intercept.
We use this to find the slope of $y=x+3$.
We rewrite the equation with a coefficient for $x$: $y=1x+3$
Since $1$ replaces $m$ in the equation, it is the slope we are looking for, and would be the slope of a parallel line.
