计算:(1)(-2a+3b)(-2a-3b)(2)(x+y-2)(x-y+2)(3)(3x-4y)2(4)(2x-y-3
3a(x+y)-2b(x+y)=(x+y)(?)
计算:(1) (2x-3y)+(5x+4y) (2) (8a-7b)-(4a-5b)
利用乘法公式计算(x+y)(x²+y²)(x-y)(x的四次方+y四次方)(a-2b+3)(a+2b
对于有理数a,b,定义:a*b=3a-2b,若x,y均为有理数,试计算【(x+y)*(x-y)】*2 x.
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-4y)-[-(2y+x)+(x-3y)]-6x
设A={(x,y)|3x+2y=1},B={(x,y)|x-y=2},C={(x,y)|2x-2y=3},D={(x,y
设A=2x-3xy+y+x-3y,B=4x-6xy+2y+4x-y,若|x-3a|+(y+3)=0,且B-2A=a.求A
设A={(x,y)|y=-2x+3,x,y∈R},B={(x,y)|y=(4m-3{m}^{2})x+1,x,y∈R},
分解公因式的题 x(a-x)(a-y)-y(x-a)(y-a)-ab(a-b)^2+a(b-a)^2a^3b-ab2ab
初一几道计算忘了.x²-5x=2a(x-2y)-3b(2y-x)-4c(x-2y)=-5x²y
已知|x-y-3|+(a+b+4)²=0,求2a+2b-(a+b)分之(x-y)²-3(y-x)的值