计算 (-x^2+3xy-1/2y^2)-(-1/2x^2+4xy-3/2y^2) 谢
计算3xy[2xy-x(y-2)+x-1]
计算:(5-xy/x^3-x^2y)/(1-5/xy)^2*(y-x)^3
计算:3xy[2xy-x(y-2)+x]
(x^2+xy/x-y)/(xy/x-y)计算
计算(3x^3y-x^2y+1/2xy)÷(-1/2xy)
计算3x[xy-2x(1/y-x/3]+3y(x²-y²)
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
已知:x-y=1,xy=-2.求:(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
x-y=1,xy=2.求:(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
.已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
xy(xy+1)+(xy+3)-2(x+y+2分之一)-(x+y-1)的平方