(1999•西安)化简x4+x2y2(x≤0)( ) A.xx2+y2 B.-xx2+y2 C.x(x+y) D.-x(x+y)
问题描述:
(1999•西安)化简
(x≤0)( )
x4+x2y2
A. x
x2+y2
B. -x
x2+y2
C. x(x+y)
D. -x(x+y)
答
∵x≤0
∴
=
x4+x2y2
=-x
x2(x2+y2)
.
x2+y2
故选B.