(15届江苏初一1试)已知a+b=0,a≠b,则化简ba(a+1)+ab(b+1)得(  ) A.2a B.2b C.2 D.-2

问题描述:

(15届江苏初一1试)已知a+b=0,a≠b,则化简

b
a
(a+1)+
a
b
(b+1)得(  )
A. 2a
B. 2b
C. 2
D. -2

b
a
(a+1)+
a
b
(b+1),
=b+
b
a
+a+
a
b

=(a+b)+(
b
a
+
a
b
),
又a+b=0,a≠b,可得:
a
b
=
b
a
=-1,
b
a
(a+1)+
a
b
(b+1)

=(a+b)+(
b
a
+
a
b
),
=-2.
故选D.