1.(x+y)²-4xy=( )²2.x²-（ ）+25y²=（ )²3.x²-8x²y²+16y四次方=（ ）²4.7.2²-2.8²= .

1.(x+y)²-4xy=( )²2.x²-（ ）+25y²=（ )²3.x²-8x²y²+16y四次方=（ ）²4.7.2²-2.8²= . 6x²-xy-15y²=0 求x²-2xy+4y²/2x²-3xy-3y²告诉下 6x²-xy-15y²=0 求2x²-3xy-3y²分之x²-2xy+4y² 3x²-y²=8x²＋xy＋y²=4 已知x² -XY = 2,Y² -XY= 5,求x² - 4x Y+ Y² = 2x² + xY -3Y² = x² 已知x² -XY = 2,Y² -XY= 5,求x² - 4x Y+ Y² = 2x² + xY -3Y² = x² + xY- 2Y² =求x² - 4x Y+ Y² = 4x²y-xy² 1 3x²+4xy-y²=2 4xy+1-4x²-y²= x²-7xy+12y²=0｛x²+4xy+4y²=14 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+xy=3,xy+y²=—2,求x²-y²的值?x²+4xy+3y²的值?2x²-xy-3y 已知2x+3y=0,求代数式1.5x+4y/3x-2y 2.x²+xy-y²/x²-xy+y² 若x²+y²+4x-10y+29=0,则x²y+xy²= x²+y²+4x-8y+20=0,求分式x²-y²/xy的值 若x²+xy-2y²=0,则x²+3xy+y²/x²+y² x²+xy-2y²=0则x²+3xy+y²/x²+y² 已知2x²-3y²=xy,(xy≠0),求值（4xy-x²）／(xy+2y²)的值 已知x-2y=3,x²-2xy+4y²=11,求①xy ②x²y-2xy² 已知,x²+2y²-2xy-4y+4=0,求x²+y²的值