step 1
Find the slope
we need two points
take the points (0,3) and (1,0)
m=(0-3)/(1-0)
m=-3
step 2
Find the equation of the line in slope intercept form
y=mx+b
we have
m=-3
b=3
substitute
y=-3x+3
step 3
Find the equation of the line in point slope form
y-y1=m(x-x1)
we have
m=-3
point (0,3)
y-3=-3(x-0)
y-3=-3x
step 4
standard form
AX+By=C
we have
y=-3x+3
3x+y=3 -----> standard form