(1/2x+1/3y)÷(2/3x+1/2y)化简,
化简:(x+y)+(2x+y/1*2)+(3x+y/2*3)+...+(9x+y/8*9)
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
1) (x+y)^2-(x+y)^3 2) (x-y)^2-(x-y)^3 3)(x-y)^2-(y-x)^3 因式分解
先化简再求值:(x-2y)²-(x+2y)(x-2y)-(x-3y)(x-y).其中x²+9y
2(x+y)-3分之2(x-y)-3(x+y)+3分之2(x-y)化简 其中x=-2,y=1
数学题化简再求值(1/x-y+1/x+y)÷x^2 y^2/x^2-y^2,其中x=3,y=-√2
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
已知x-y=1,y≠0,求{(x+2y)²+(2x+y)(x+4y)-3(x+y)(x-y)}÷y的值.
[(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y
计算(1)x/x+y-x/x-y (2)a+2+4/a+2 (3)x^2-y^2/xy÷(x+y)
因式分解 (1)6(x-y)^3-3y(y-x)^2 (2)x(x-y)(a-b)-y(y-x)(
10/x+y+3/x-y=-5 15/x+y-2/x-y=-1(用换元法解此方程组)