Point (0,3) is the y - intercept of the function because it is the point where x = 0.
A y - intercept is when x is 0 and y is a point
If you get a equation like this:
y = 4x
The y - intercept would be zero since there is no number for y
If you get a equation like this
y = 4x + 1
The The y - intercept would be 1 since there is a b
Standard form: y = mx + b
b = y-intercept