persamaan garis lurus yang bergradien -2 dan titik ( 0 , 3 )

y-y1=m(x-x1)
y-3=-2(x-0)
y-3=-2x+0
y+2x-3=0

titik 0 = x1
titik 3 = y1

persamaan garis lurus= (y-y1) = m(x-x1)
                                        (y-3) = -2(x-0)
                                        (y-3) = -2x+0
                                        y+2x = 0+3
                                        y+2x = 3 atau
                                        y=-2x+3 atau
                                        y+2x-3 = 0