计算:(1)-2xy(3x²y-4xy²);(2)(a-2b)(a²+2ab+4b
计算a-b/a+b*a四次方-a²b²/a²-ab (2)4x²-4xy+y
x²(x+y)(y-x)-xy(x+y)(x-y) 已知a+b=4,ab=-2,求多项式3a²b+3
已知2x²+xy=a,3y²+2xy=b,求4x²+8xy+9y²的值(用a,b
已知A=4x²-4xy+y²,B=x²+xy-5y²,求:⑴A-3B;⑵2A+B
已知2x²+xy=a,3y²-2xy=b,求4x²+8xy-9y²的值(用含a,
3a-3b/10ab*25a^b3/a^-b^= x^-4y^/x^+2xy+y^/x+2y/2x^+2xy
一,计算(1)5a^2b*(-2ab^2)^3 (2)(12x^3y-20xy)/4xy二,化简,求值(m+2n)^2-
(1).设A=2X²-3Xy+y²+X-3y,B=4X²-6xy+2y²+4X-
计算:(1)3a/4b乘16b/9a²,(2)12xy/5a÷8x²y,(3)(-3xy)÷2y
1、-3x²y+2x²y+3xy²-2xy² 2、4a²+3b
化简分式;(1)3xy/42x-3xy(2)a-b/a²-b²(3)x²+2xy+y
A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y,若x=