The slope is defined as the ratio between the vertical and horizontal changes.
You can see that, in order to decrease y by 1, you have in increase x by 4. So, the slope is -1/4.
The y intercept is -6, because the line passes through the point (0, -6).
So, we can write the line in the form
[tex]y=mx+q[/tex]
as required, where m is the slope and q is the y intercept:
[tex]y = -\dfrac{x}{4}-6[/tex]