问题
解答题
先化简再求值:5xy2-[2x2y-(2x2y-xy2)]-4xy2-x,其中,x=-
|
答案
5xy2-[2x2y-(2x2y-xy2)]-4xy2-x
=5xy2-[2x2y-2x2y+xy2]-4xy2-x
=5xy2-xy2-4xy2-x
=-x
当x=-
,y=161 2
时,原式=-(-2 3
)=1 2
.1 2
先化简再求值:5xy2-[2x2y-(2x2y-xy2)]-4xy2-x,其中,x=-
|
5xy2-[2x2y-(2x2y-xy2)]-4xy2-x
=5xy2-[2x2y-2x2y+xy2]-4xy2-x
=5xy2-xy2-4xy2-x
=-x
当x=-
,y=161 2
时,原式=-(-2 3
)=1 2
.1 2