x+y+x-y+是什么公式

宰灵孔1382已知x+y=1,xy= - 二分之一.求x(x+y)(x - y) - [x(x+y)^2] -
程家汤18550242454 ______ x(x+y)(x-y)-[x(x+y)^2]=(x+y)*[x(x-y)-x(x+y)]=(x+y)*[x^2-xy-x^2-xy]=(x+y)*(-2xy)=1*(-2)(*-1*2)=1

宰灵孔1382如果xy表示有理数,在什么条件下x+y和x - y互为相反数,什么情况下和为2 -
程家汤18550242454 ______[答案] 解析 相反数相加=0 所以当x+y+x-y=0时 2x=0 即x=0是互为相反数 x+y+x-y=2 2x=2 x=1 所以x=1时,和是2

宰灵孔1382化简x/x+y + x/x - y -
程家汤18550242454 ______[答案] x/(x+y) + x/(x-y) =[x(x-y)+x(x+y)]/[(x-y)(x+y)] =2x^2/[(x-y)(x+y)]

宰灵孔1382x(x+y)(x - y) - x(x+y)的平方怎么提公因式 -
程家汤18550242454 ______ x(x+y)(x-y)-x(x+y)² =x(x+y)[(x-y)-(x+y)] =x(x+y)(x-y-x-y) =-2xy(x+y)

宰灵孔1382x(x+y)(x - y) - x(x+y)的二次方,提公因式 -
程家汤18550242454 ______ 您好: x(x+y)(x-y)-x(x+y)²=x(x+y)(x-y-x-y)=-2xy(x+y) 不明白,可以追问 如有帮助,记得采纳,谢谢 祝学习进步!

宰灵孔1382完全平方差公式怎么解来的?这些公式都是怎么解得?1、(x - y)? - (x+y)?(或者全是+呢?)2、[x - y+3]? -
程家汤18550242454 ______[答案] (x-y)��-(x+y)�� =(x-y+x+y)(x-y-x-y)=-4xy [x-y+3]��=(x-y)^2+6(x-y)+9=x^2-2xy+y^2+6x-6y+9

宰灵孔1382 - │x│ - │y│≤x+y≤│x│+│y│这个数学公式怎么验证成这个公式│x+y│≤│x│+│y│大家对数学上懂的请给我一个清晰的验证步骤在此谢谢大家 -
程家汤18550242454 ______[答案] 数轴上来理解 当a>0时,-a≤x≤a等价于|x|≤a -(│x│+│y│)≤x+y≤│x│+│y│ 等价于│x+y│≤│x│+│y│

宰灵孔1382( - x - y)(x+y)和( - x - y)(x - y)的答案,最好是用完全平方差的公式.今天就要啊! -
程家汤18550242454 ______[答案] (-x-y)(x+y) =-(x+y)² =-x²-2xy-y² (-x-y)(x-y) =(-y-x)(-y+x) =(-y)²-x² =y²-x²

宰灵孔1382x(x+y)(x - y) - (x+y)的平方 -
程家汤18550242454 ______[答案] =(x+y)[x(x-y)-(x+y)] =(x+y)(x²-xy-x-y)

宰灵孔1382分解因式:(x+y)3次方(x - y) - (x+y)(x - y)3次方 -
程家汤18550242454 ______[答案] 原式=(x+y)(x-y)[(x+y)²-(x-y)²] =(x+y)(x-y)(x+y+x-y)(x+y-x+y) =4xy(x+y)(x-y)