1.已知x^2+6xy+9y^2+|y-1|=0,则x+y=?2.4a^3-16a^2+16a=?3.-1/2x^2+xy-1/2y^24.(x^2+2x)^2+2(x^2+2x)+15.y^3-4y^2+4y6.一直a、b、c分别为三角形ABC的三条边,求证(a^2+b^2-c^2)^2-4a^2b^2小于0

已知x^2-6xy+9y^2=0,求(x-y)/(x+y) 已知x-xy=8,xy-y=-9,求x+y-2xy的值 1.已知x--xy=8,xy--y=--9,求x+y--2xy的值 已知X+y=6,xy=7 求x^2y+xy^2=已知X+y=6,xy=7 x^2y+xy^2 已知xy/x+y=6,求3x-2xy+3y/-x+3xy-y的值. 已知(xy)/(x+y)=6求(3x-2xy+3y)/(-x+3xy-y)的值. 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y 已知2x^2+6x+y^2=2xy-9,求x^y 已知:x/y=-2,求x^2-2xy-3y^2/x^-6xy 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) 已知x^2+9y^2-2x-6y+2=0,求{-（xy/（x-y）^2}^4*(y^2-xy/x)^3*x^4/y^10/(x/xy-y^2)^5的值 1.已知x+y=-4,xy=3,求5（2分之1xy+2y）+[6x-(2xy+y-3x)]的值2.已知（x+3）^2+|x-y+10|=0求代数式5x^2y-[2x^2y-(3xy-xy^2)-3x^2]-2xy^2-y^2的值 已知x+y=6,xy=4,求x^2y+xy^2的值~ 已知x+y=6,xy=-3,则x^2y+xy^2=? 已知x+y=6,xy=-3,则x∧y+xy∧2= 已知：x^2减6xy加9y等于0.则x：y等于____. 已知；x+y=4,x-y的绝对值=6,求xy(y的平方+y)-y的平方（xy+2x）-3xy先化简再求值 已知x+y=4,x-y=6,化简xy（y²+y）-y²（xy+2x）-3xy