( – ) ( – )
px
q
x a
+x b
, a ≠ b
A
B
x – a
x – b
+
2 ( – )2
px
q
x
a
+
(
)
2
A
B
x – a
x – a
+
3 2
( – ) (
) (
)
px
qx
r
x
a
x – b
x – c
+
+
A
B
C
x – a
x – b
x –c
+
+
4 2
2
( – ) (
)
px
qx
r
x
a
x – b
+
+
2
A
B
C
(
)
x – a
x – b
+x – a
+
5