Let's take two points from your line. where it intersects with x-axis and y-axis:
A(0; -3) and B(3;0)
Now, to find the slope of the line, we use this formula:
[tex]m=\frac{y_{1}-y_{2}}{x_{1}-x_{2}}[/tex], where [tex]m[/tex] is the slope.
So, the slope of given line is:
[tex]m=\frac{-3-0}{0-3}=\frac{-3}{-3}=1[/tex]
