y=(x)^1 2,x y=2,在x轴,求其二重积分-搜答案-智慧作业帮

x-xy=8(1)xy-y=-9(2)则有(1)-(2):X-XY-XY+Y=X+Y-2XY=8-(-9)=17

(x^2+3xy+2y^2)/(x^2y+2xy^2)=(x+2y)(x+y)/[xy(x+2y)]=(x+y)/(xy)将x+y=7,xy=12代入(x+y)/(xy)=7/12

x^2+xy+y=14y^2+xy+x=28两式相加x^2+y^2+2xy+x+y=42(x+y)^2+(x+y)-42=0(x+y-6)(x+y+7)=0x+y=6或x+y=-7

y是多少原式=(x+y)(x-y)/(x-y)²+x(y+3)/x(y+3)=(x+y)/(x-y)+1=(x+y+x-y)/(x-y)=2x/(x-y)=1/(1/2-y)再问：y=3

第一步,找|x|+|y|

(-3x^y+2xy)-(4x^+xy)=-3x^y+2xy-4x^-xy=-3x^y+xy-4x^所以填上-3x^y+xy-4x^

（1）∵xy+x=-1①，xy-y=-2②，∴①-②得x+y=1；（2）先把xy+x=-1，xy-y=-2的值代入代数式，得原式=-x-[2y-1+3x]+2[x+4]=-x-2y+1-3x+2x+8

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

（4xy+12y)+[7x-(3xy+4y-x)]=4xy+12y+7x-3xy-4y+x=xy+8x+8y=xy+8(x+y)=(-2)+8*3=-2+24=22

7或者-8再问：求过程^_^再答：两个等式两边相加

2(x+xy)-[(xy-3y)-x]-(-xy)=2x+2xy-xy+3y+x+xy=3x+3y+2xy=3（x+y）+2xy=3*（-2）+2*3=0

∵x-y=4xy，∴2x+3xy-2yx-2xy-y=2(x-y)+3xyx-y-2xy=8xy+3xy4xy-2xy=112．故答案为：112．

是这样不?

X²+2xy+y²/xy乘x²-2xy+y²/xy+y²=(x+y)²/xy×(x-y)²/y(x+y)=(x+y)(x-y)&#

x²+xy=12 xy+y²=13

两式相加得到x+y=5,相减得y-x=1/5,故x=12/5,y=13/5xy=156/25,因为要求的都是正数,而且xy同正负,所以只考虑x,y正数即可故x²+y²=（x+y）^

(1)X+Y=M(2)2X-Y=6(1)+(2)3X=M+6X=(M+6)/3=M/3+2Y=2X-6=(2M-6)/3=2M/3-2XY是整数所以M是3的倍数XY

先化简在求值(-1/3XY)²×[xy(2x-y)-2x(xy-y)²],=1/9x²y²*(2x²y-xy²-2x²y+2xy&

x²-7xy+12y²=0(x-3y)(x-4y)=0x1=3yx2=4yx=3y时原式＝9y²-3y²+y²/6y²=7/6x=4y时原式

3(1,4)和0(2,2)