P1
(
2
,
4
)
m
=
3
(
Y
-
Y1
)
=
m
(
X
-
X1
)
(
Y
-
____________________
)
=
____________________
(
X
-
____________________
)
____________________
-
____________________
=
____________________
-
____________________
-
(
-
3X
+
____________________
-
4
+
____________________
)
____________________
+
____________________
+
____________________
=
0
