1/x2−3x+2+1/x2−5x+6+1/x2−4x+3.

问题描述:

1
x2−3x+2
+
1
x2−5x+6
+
1
x2−4x+3

原式=

1
(x−2)(x−1)
+
1
(x−2)(x−3)
+
1
(x−1)(x−3)

=
x−3+x−1+x−2
(x−1)(x−2)(x−3)

=
x−3+x−1+x−2
(x−1)(x−2)(x−3)

=
3(x−2)
(x−1)(x−2)(x−3)

=
3
(x−1)(x−3)