X-Y除Y-搜答案-智慧作业帮

解【(x+2y)的平方-(x+y)(x-y)-5y方】÷(2x)=[x^2+4xy+4y^2-(x^2-y^2)-5y^2]÷(2x)=[x^2+4xy+4y^2-x^2+y^2-5y^2]÷(2x)

[(x的平方+y的平方)-(x-y)的平方+2y(x-y)]/4y=(x^2+y^2-x^2+2xy-y^2+2xy-2y^2)/4y=(2x-y)/2=4022/2=2011

[(3x+4y)的平方-3x(3x+4y)]除(-6y)=（3x+4y)(3x+4y-3x)/(-6y)=(3x+4y)*4y/(-6y)=-(3x+4y)*2/3=-2/3*（3x+4y)

原式=1/4y[x^2-4*y^2-(x^2+8*xy+16y^2)]=1/4y(-8*xy-20*y^2)=-2x-5y代入得：原式=(-2)*(-2)-5(-3)=19

[(x-y)²-(x+y)(x-y)]除(-2y)+y=[x²-2xy+y²-(x²-y²)]/(-2y)+y=(-2xy+2y²)/(-2

是{（x+y）2-（x+y）（x+3y）-5y}/2y=【（x+y）（2-x-3y）-5y】/2y=(x+y)(2-x-3y)/5y-2.5带入数字（-2+1/2）(2+2-1.5)/2.5-2.5=

是否这样：√[x+y）/xy²]÷√x（x+y）=√[（x+y）/（x+y）x²y²]=√1/x²y²=1/|x||y|再问：是这样麻烦了~再答：知道

2y=x-3带入[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]/4x=[(3x+x-3)(3X-x+3)-(x+x-3)(5x+3-x)]/4x=(8x2-6x=12x-9-8x2=12

｛（x的平方+y的平方）-（x的平方-y的平方）+2y(x-y)}除4y=(2y^2+2y(x-y)/(4y)=2xy/(4y)=x/2

原式=[(x+2y)/(x+y)]×[xy/(x+2y)]÷[(x+y)/xy]=[(x+2y)/(x+y)]×[xy/(x+2y)]×[xy/(x+y)]=x²y²(x+2y)/

(x-y)[(x+y)+x-y]+4y-2y^2=2x(x-y)+4y-2y^2=2[x^2-xy+2y-y^2]所以=2[1-2+4-4]/8=-1/4

反比例,一般地,如果两个变量x、y之间的关系可以表示成y＝k／x(k为常数,k≠0)的形式,那么称y是x的反比例函数.你再想想,x=7÷y可以化成xy=7,乘积不变,所以为反比例

原式=(x^2-4y^2-x^2-8xy-16y^2)/(4y)=-5y-2x=-25-4=-29

你好第一个y=1/3x=（1/3）/x是反比例函数.

(x+y)(x-y)-(x-y)²-6x²y除2y+(2xy)²除(-4xy)=x²-y²-x²+2xy-y²-6x²-

13y-4x

正在做啊再问：恩再答：cos[π/2-(π/3+x)]=cos(π/6-x)=sin(π/3+x)y=sin(x+π/3)cos(π/6-x)=sin(x+π/3)sin(π/3+x)=sin

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

原式=(x²-4y²-x²-4xy-4y²)×(2/y)=(-8y²-4xy)×(2/y)=-16y-8x=-4+8=4

2个{3,-1}全为正时3全为负时-11个正1个负时-1