Y= mx + b is the form of slope
b also is y-intercept
So the y-intercept is always on y-axis
You can see that the line fall on number 5 so
Y=mx + 5
Mx is the slope want to find the slope the form is
Y2 -y1 / x2-x1
For example (0,5) and (6,3)
3-5 = -2
6-0 = 6
-2/6 = -1/3
Y= -1/3 +5