The equation of the linear line has a general form:
y=mx+c where
m is the slope = 2
c is the y-intercept
So, the equation of the line now has the form:
y=2x+c
We are given that (4,5) belong to this line, so, we will use this point and substitute in the equation to get the value of c as follows:
y=2x+c
5=2(4)+c
5=8+c
c = 5-8=-3
Based in the above, the equation of the line is:
y = 2x - 3