化简分式:b/(a−b)(b−c)+c/(b−c)(c−a)+a/(c−a)(a−b)=_.

问题描述:

化简分式:

b
(a−b)(b−c)
+
c
(b−c)(c−a)
+
a
(c−a)(a−b)
=______.

原式=

b(c−a)+c(a−b)+a(b−c)
(a−b)(b−c)(c−a)

=
bc−ab+ca−bc+ab−ac
(a−b)(b−c)(c−a)

=0.