How do I right an equation from slope intercept form

Given the graph of a line
We will write the slope-intercept form of the equation of the line
AS shown, the line passes through the points (0, 3) and (-1, 0)
The equation of the line is: y = m * x + b
Where (m) is the slope of the line
(b) is the y-intercept
The slope of the line =
[tex]slope=m=\frac{rise}{run}=\frac{y_2-y_1}{x_2-x_1}=\frac{0-3}{-1-0}=\frac{-3}{-1}=3[/tex]the value of (b) = y-interept = the value of (y) when (x=0)
So, b = 3
So, the equation of the line will be:
[tex]y=3x+3[/tex]