1.设A=｛2,-1.x²-x+1｝B=｛2y,-4,x+4｝C=｛-1,7｝且A∩B=C求xy的值2.设A=｛a²,a+1,-3｝B=｛a-3,2a-1,a²+1｝A∩B=｛-3｝求a的值要有过程啊

Question

1.设A=｛2,-1.x²-x+1｝B=｛2y,-4,x+4｝C=｛-1,7｝且 A∩B=C 求x y的值
2.设A=｛a²,a+1,-3｝ B=｛a-3,2a-1,a²+1｝ A∩B=｛-3｝求a的值
要有过程啊

Answer 1

1.设A=｛2,-1,x²-x+1｝B=｛2y,-4,x+4｝C=｛-1,7｝且 A∩B=C 求x y的值
A=｛2,-1,7}
B={-4,-1,7}
得x²-x+1=7
所以x=3,x+4=7
2y=-1
y=-1/2
2.设A=｛a²,a+1,-3｝ B=｛a-3,2a-1,a²+1｝ A∩B=｛-3｝求a的值
a²+1>a²
a²+1>-3
所以有a²+1≠a+1
得a≠0
a-3≠-3
必有2a-1=-3
得a=-1