the equation of a line that pass through the point (x1,y1) and has a slope of m is
y-y1=m(x-x1)
the find the slope
the slope of the line that passes through the points (x1,y1) and (x2,y2) is
(y2-y1)/(x2-x1)
given
(2,0) and (0,3)
slope=(3-0)/(0-2)=3/-2=-3/2
slope=-3/2
let's do (2,0)
x1=2
y1=0
m=slope=-3/2
y-y1=m(x-x1)
y-0=-3/2(x-2)
y=-3/2(x-2)
y=(-3/2)x+3