求证:x^2-2xy+y^2+x+y-4不能分解为两个一次因式的乘积.

因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) 已知x,y都是正整数,求证x^3+y^3>=x^2y+xy^2 已知x,y∈R,求证:x^2+y^2≥xy+x+y-1 已知x,y,z∈R,求证:x^2+y^2>=xy+x+y-1 求证3x^2-8xy+9y^2-4x+6y+13＞0 x>y>o xy=2 求证 (x2+y2)除以x-y大于等于4 已知xy>0且x≠y,求证：log(x^4+6x^2y^2+y^4)>log(4xy(x^2+y^2)) 已知4x²+4xy+y²-4x-2y+1=0,求证2x²+3xy+y²-x-y=0 x大于0,y大于0,x不等于y,且x+y=(x^2)+(y^2)+xy,求证1小于x+y小于4/3 已知,x＞0,y＞0,x≠y,且x+y=x^2+y^2+xy,求证：1小于x+y小于4/3 (x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) 计算:2xy/(x+y)².(x+y)/4y 已知xy为任意实数,求证x^4+y^4≥1/2xy(x+y)^2 已知xy为任意实数,求证x^4+y^4≥1/2xy(x+y)^2 求证：（x+y)^3+3xy（1-x-y)-1=（x+y-1)（x^2+y^2-xy+x+y+1) (x^-4y^)/(x^+2xy+y^)/(x+2y)/(2x^+2xy) 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 (-x-y)(x^2+xy+y^2)