Explanation:
the slope is the ratio "y coordinate change / x coordinate change" when going from one point on the line to another.
so, for example, when using the first 2 points (0, -5) and (1, -3) we see
x changes by +1 (from 0 to 1)
y changes by +2 (from -5 to -3).
so, the slope is +2/+1 = 2
the y-intercept is the y value when x=0. so in this case -5.
this is because it identifies the point where the line intercepts the y-axis (which is the reason why x=0).
the intercept point is then (0, -5).