garis b tegak lurus h dan memotong sumbu x di titik M. persamaan garis b adalah tolong yaaa

Mp = Mb
Mb = -y/x
        -2/4 = -1/2
Mh x Mb = -1
Mh x -1/2 = -1
Mh = 2
Mh = -y/x
2 = -2/x
x = -1
Persamaan garis b = y - 0 = -1/2 (x + 1)
                                  2y = -x - 1
                                  2y + x +1 = 0