2(x+y)-4(x-y)=4化简为多少？x+y2十x-y6=-1化简为多少？

2(x+y)-4(x-y)=4化简为多少？x+y/2十x-y/6=-1化简为多少？

2(x+y)-4(x-y)=4化简为

去括号 2X+2y-4X+4y=4

合并同类项6y-2x=4

等式两边约分 3y-x=2

x+y/2十x-y/6=-1化简为

合并同类项 2x-y/3=-1

去分母 6x-y=-3

化简(x+y)√(x-y/x+y)-(x-y)√(x+y/x-y)+√(1/x^2-y^2)

解：

(x+y)√(x-y/x+y)-(x-y)√(x+y/x-y)+√(1/x^2-y^2)

=√(x+y)^2(x-y)/(x+y) -√(x-y)^2(x+y)/(x-y) +√(1-x^2y^2)/x^2

=√(x^2-y^2) - √(x^2-y^2) +√(1-x^2y^2)/x^2

=√(1-x^2y^2)/x^2

=√(1+xy)(1-xy)/x^2

1/2(x+y+z)的平方+1/2(x-y-z)(x-y+z)-z(x+y)化简为多少？须过程，谢谢！

1/2(x+y+z)的平方+1/2(x-y-z)(x-y+z)-z(x+y)

=½(x²+y²+z²+2xy+2xz+2yz)+½(x²-2xy+y²-z²)-zx-zy

=½x²+½y²+½z²+xy+xz+yz+½x²-xy+½y²-½z²-zx-zy

=x²+y²

化简：2（x+y)-2/3（x-y)+1/4(x+y)+2/3(x-y)

2（x+y)-2/3（x-y)+1/4(x+y)+2/3(x-y)

=2(x+y)+1/4(x+y)-2/3(x-y)+2/3(x-y)

=2(x+Y)+1/4(x+y)

=(2+1/4)(x+y)

=9/4(x+Y)

不懂的欢迎追问，如有帮助请采纳，谢谢!

化简：（1）-2(x+y)^23(x+y)^3=——（2）-2（x-y)^41/2(y-x)^2

(1)-6（x+y）^5

(2)-(x-y)^6

(x-y/x+y)-(x+y/2x-y) 能化简成什么

原式=x--y/x+y--x--y/2x+y

=--3y/2x+2y。

化简:[4xy(x-y)^-1 + (xy^-1 - x^-1y)/(x^-1 + y^-1)] / (x+y)^2

[4xy(x-y)^-1 + (xy^-1 - x^-1y)/(x^-1 + y^-1)] / (x+y)^2

=[4xy/(x-y)+(x/y-y/x)/(1/x+1/y)]/(x+y)^2

=[4xy/(x-y)+((x^2-y^2)/xy)/((x+y)/xy)]/(x+y)^2

=[4xy/(x-y)+(x-y)]/(x+y)^2

=[(4xy+(x-y)^2)/(x-y)]/(x+y)^2

=[(x^2+2xy+y^2)/(x-y)]/(x+y)^2

=[(x+y)^2/(x-y)]/(x+y)^2

=1/(x-y)

化简3(x-y)^-1/2(x+y)+3/4(x-y)^+3/2(x+y) 其中x-y=2 x+7=-3

题目应是：3(x-y)^2-1/2(x+y)+3/4(x-y)^2+3/2(x+y) 其中x-y=2 x+y=-3

3(x-y)^2-1/2(x+y)+3/4(x-y)^2+3/2(x+y)

=15/4(x-y)^2+(x+y)

=15/42^2+(-3)

=15-3

=12

化简1/2x-1/x+y（x+y/2x-x-y）

原式=1/2x-1/(x+y)[(x+y)/2x-(x+y)]

=1/2x-1/(x+y)×(x+y)(1/2x-1)

=1/2x-(1/2x-1)

=1/2x-1/2x+1

=1

1化简(x-y/2)的2次-(x+y/2)的2次

(x-y/2)的2次-(x+y/2)的2次

=[(x-y)/2]²-[(x+y)/2]²

=[(x-y)/2+(x+y)/2][(x-y)/2-(x+y)/2]

=x(-y)

= -xy

假设硬币只能投到正反面,且概率相同

N=X+Y这就是他们的关系,希望我有理解题目的意思

回答的完善点,每一个面投到指定次数的概率是：

P=binopdf(n,05,k)

=nCk(05)^k(05)^(n-k)

-n!/[k!(n-k)!](05)^k(05)^(n-k)

这是一个简单的二项式概率分布,n是总投到的次数而k是希望投中的次数