设全集U={1,3,5,7}且A={x|x2+mx+n=0},若CuA={5,7},求m,n的值
问题描述:
设全集U={1,3,5,7}且A={x|x2+mx+n=0},若CuA={5,7},求m,n的值
答
A的两根是1 3
1+m+n=o
9+3m+n=0
m=-4 n=3