Enter the slope-intercept equation of the line that has -2 and y-intercept (0,7)

So first of we have to know that the equation has to be y=mx+b. So now we plug in 0 & 7, the 0 replaces the x and the 7 replaces the y and we already know the slope which is a -2. So then when we plug all it in we have 7=-2(0)+b.
7=-2(0)+b
7=0+b
subtract 0 from both sides and then we get:
7=b
then we put it into a equation which is:
y= -2x+7