当丨x-1丨+丨y-3丨=0时,探究并计算:1/xy+1/(x+2)(y+2)+1/(x+4)(
合并同类项并计算 -3[y-(3x²-3xy)]-[y+2(4x²-4xy)]其中,x=3,y=1/
计算3xy[2xy-x(y-2)+x-1]
当x=2,y=1时,代数式x^4-xy^3-x^3y-3x^2y+3xy^2+y^4
当x-y=1时,求x^4-xy^3-x^3y-3x^2y+3xy^2+y^4的值
当|x-1|+|y+3|=0时,求xy分之一+(x+2)(y+2)分之一+(x+4)(y+4)分之一+(x+6))(y+
将x(x+y)(x-y)-x(x+y)2进行因式分解,并求当x+y=1,xy=−12
计算3x[xy-2x(1/y-x/3]+3y(x²-y²)
当x-y=1,求x^4-xy^3-x^3y-3x^2y+3xy^2+y^4的值
计算:(5-xy/x^3-x^2y)/(1-5/xy)^2*(y-x)^3
先化简,再求值 :(xy-3x^2)-2(xy-2x^2-1),其中x、y满足条件丨x+2丨+(y-1)^2=0
计算:(x-2y)(1+x+2y+4y^2+2xy+x^2)
已知(x-3)²+丨1/4+y丨=0,求代数式7xy-5(x²+2y)-7(xy-x²)