化简分式:1/x2+3x+2+1/x2+5x+6+1/x2+7x+12.

问题描述:

化简分式:

1
x2+3x+2
+
1
x2+5x+6
+
1
x2+7x+12

原式=

1
(x+1)(x+2)
+
1
(x+2)(x+3)
+
1
(x+3)(x+4)

=(
1
x+1
-
1
x+2
)+(
1
x+2
-
1
x+3
)+(
1
x+3
-
1
x+4

=
1
x+1
-
1
x+4

=
3
x2+5x+4