(x+y)²=25,(x-y)²=9,求x²+y²和xy的值

已知（x+y)²=25,（x-y)²=9,求xy与x²+y²的值 (x+y)²=25,(x-y)²=9,求x²+y²和xy的值 已知:x²-6x+8y+y²+25=0,求x²+2xy+y² x²-6x+y²+8y+25=0 则x= y= (x+y)²-10(x+y)+25 1.(x+y)²-4xy=( )²2.x²-（ ）+25y²=（ )²3.x²-8x²y²+16y四次方=（ ）²4.7.2²-2.8²= . 已知(x+y)²;=8,(x-y)²;=4,求x²+y² 已知x²y²+x²+y²=10xy-16 求x,y 已知x²+y²=25,x+y=7,且x>y,求x-y的值 x²+y²-6x-8y+25=0 求y/x-x/y=? x²-4y² x+2y---------- ÷ --------分数线x²+2xy+y² x²+xyx²-4y² x+2y----------÷--------分数线x²+2xy+y² x²+xy(x+2y)(x-2y)x(x+y)=----------------(x+y)(x+y)(x+2y)(x-y)x=------(x+y)这样对了吗? 已知x²+y²+8x+6y+25=0,求x-4y/x+y的值 x²+y²-6x-8y+25=0,求y/x-x/y的值 已知x²+y²-6x-8y+25=0,求y/x-x/y的值. 已知x²+y²-6x-8y+25=0,求y/x-x/y 2x-y=2,求[(x²+y²)-(x-y)²+2y(x-y)]÷4y 已知(x²+y²)(x²+y²-6)+9=0 ,求x²+y²的值. 若x²+xy-2y²=0,则x²+3xy+y²/x²+y²