问题
选择题
一个多项式加上x2y-3xy2得2x2y-xy2,则这个多项式是( )
A.3x2y-4xy2
B.x2y-4xy2
C.x2y+2xy2
D.-x2y-2xy2
答案
(2x2y-xy2)-(x2y-3xy2)
=2x2y-xy2-x2y+3xy2
=x2y+2xy2.
故选C.
一个多项式加上x2y-3xy2得2x2y-xy2,则这个多项式是( )
A.3x2y-4xy2
B.x2y-4xy2
C.x2y+2xy2
D.-x2y-2xy2
(2x2y-xy2)-(x2y-3xy2)
=2x2y-xy2-x2y+3xy2
=x2y+2xy2.
故选C.