Answer
The slope is $0$.
The $y$-intercept is $-1$.
Refer to the graph below.
Work Step by Step
The slope of the line can be obtained by looking at the coefficient of $x$ in the slope-intercept form.
$y=-1$ which can be interpreted as
$y=0\cdot x-1$
Thus, the slope is $m=0$.
By definition, the $y$-intercept can be found as the constant in the slope-intercept form of the equation. For $y=-1$ , the constant is $-1$, therefore the $y$-intercept is $-1$.
The line $y=-1$ is horizontal and contains points whose $y$-coordinate is $-1$.
Refer to the graph above.
