计算:(1)4y.(-2xy^2) (2)(3x^2y)^3.(-4x)
计算4xy+(x-2y)的平方+(x+3y)(3y-x)
计算:3xy[2xy-x(y-2)+x]
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
计算(1)x/x+y-x/x-y (2)a+2+4/a+2 (3)x^2-y^2/xy÷(x+y)
计算(3x^3y-x^2y+1/2xy)÷(-1/2xy)
计算:(1)4y.(-2xy^2) (2)(3x^2y)^3.(-4x)
合并同类项并计算 -3[y-(3x²-3xy)]-[y+2(4x²-4xy)]其中,x=3,y=1/
通分计算:(1)2x-3/(x-1)(x-4) - x-2/(1-x)(4-x) (2)x平方-y平方/xy - xy-
计算:(-7x²y)(2x²y-3xy³+xy)
(1)3xy×(-4xy+2xy-1)(2)(x+2y)(3x-2y)+(x-2y)(3x+2y)
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
计算(2x)^-4+(4x^2)^-2 xy(x^-1+y^-1)