[(x-y)^2-(x+y)^2]/(-4xy) 化简

化简(x²y-4y²)/(x²+4xy+4y²)*[(4xy)/(x-2y)+x x^2y+4xy+4y 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) (x^-4y^)/(x^+2xy+y^)/(x+2y)/(2x^+2xy) 1.化简：x²-4y²/x²+y²+2xy÷2y+x/x²+xy. （xy-x^2)乘以(xy)/(x-y) （x^2+xy/x-y)/（xy/x-y)计算 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 化简(x平方-y平方)/(x+y)+(x平方-2xy+y平方)/(x-y) 计算:4xy-(x+y)^2/xy(x+y)(x-y)÷x^2+xy-2y^2/x^2y+2xy^2 化简:-3{y-(3x^2-3xy)}-{y+2(4x^2-4xy)} 化简4xy-3y²-3x²+xy-3xy-2x²+x²-2y²