初一数学题求(x+y)(2x-y)-(x+2y)(x-2y)的值,其中x=3,y=4

初一数学题若|x-1|+2(y+3)^2=0求x+y的值 先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y/2x-y的值 [x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013 求[(x²+y²)-(x-y)²+2y(x-y)]÷4y的值,其中2x-y=8. 已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 求(x+y)(x-y)-(x-y)的二次方,的值.其中x=5.y=2 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 数学题……555{(3x+y)(3x-y)-(x-5y)(5x-y)-(x-2y)²÷(-4x),x=-2.y 已知2/x+2/y=根号24,求 x/y(x-y) - y/x(x-y)的值