设实数xy满足4x²-5xy+4y²=5,令S=x²+y²,则1/smax+1/
设实数xy满足4x²-5xy+4y²=5,令S=x²+y²,则1/smax+1/
实数x、y,满足4x²+4y²-5xy=5.设s=x²+y²,求s的最小值的倒数
设实数X,Y满足x²+2xy+4y²=1,则x+2y的最大值为 .PS:
1 3x²+4xy-y²=
已知实数x、y满足5x²-3xy+1/2y²-2x+1/2y+1/4=0 求x、y的值
已知实数x,y满足x²+4y²=4.求f(x,y)=x²+2xy+4y²+x+2
已知实数x、y满足x²+4xy+4y²-x-2y+4分之1=,则x+2y的值,
1、已知xy满足(x+1)²+1y+21=0试求-2xy·5x²y+(0.5x²y&sup
3x²-4xy+y²
1-x²+2xy-y²
设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y.若x
问已知x²+y²=7,xy=-2,求5x²-3xy-4y²-11xy-7x&su