问题补充:
已知A=-x2y+7xy2-2,B=-2x2y+4xy2-1
(1)求A-B
(2)若|x+2|+(y-1)2=0,求A-B的值.
答案:
解:(1)A-B=(-x2y+7xy2-2)-(-2x2y+4xy2-1)
=-x2y+7xy2-2+2x2y-4xy2+1
=x2y+3xy2-1;
(2)∵|x+2|+(y-1)2=0,
∴x=-2,y=1,
当x=-2,y=1时,原式=4-6-1=-3.
解析分析:(1)分别将A和B代入,表示出A-B,继而去括号,然后合并同类项即可得出
时间:2021-11-19 16:44:27
已知A=-x2y+7xy2-2,B=-2x2y+4xy2-1
(1)求A-B
(2)若|x+2|+(y-1)2=0,求A-B的值.
解:(1)A-B=(-x2y+7xy2-2)-(-2x2y+4xy2-1)
=-x2y+7xy2-2+2x2y-4xy2+1
=x2y+3xy2-1;
(2)∵|x+2|+(y-1)2=0,
∴x=-2,y=1,
当x=-2,y=1时,原式=4-6-1=-3.
解析分析:(1)分别将A和B代入,表示出A-B,继而去括号,然后合并同类项即可得出
已知集合A={x x2 xy} B={1 x y} 且满足A=B 求实数x y?的值.
2021-04-25