若实数x,y满足4x方 2x y方 y=0

∵|2x-3y+1|+(x+3y+5)的二次方=0∴2x-3y+1=0x+3y+5=0x=-2y=-1∴（-2x*y）的二次方（-y的二次方）×6xy平方的值=4x⁴y*(-y²

因为3x方+xy-2y方=0,即（x+y)(3x-2y)=0,而x+y≠0,所以3x-2y=0原式=[（x+y)^2-4xy]/[(x+3y)(x-y)/(x+3y)(x-3y)=(x-3y)/(x+

k=(y+2)/(x+1)所以k就是过点(-1,-2)的直线的斜率x,y满足x^2+y^2=1所以就是求过点(-1,-2)的直线和单位圆有公共点是斜率的取值范围显然相切时有最值y+2=kx+kkx-y

即(3x-4y)(x+y)=03x=4y或x=-y若3x=4yy=3x/4则y²=9x²/16,xy=3x²/4原式=(3x²/4-3x²)/(9x&

再问：图片看不全再答： 能看到了吧？

xy^2=4x+2y=x+y+y≥3三次根号（xy^2）＝3三次根号4

5x²-3xy+1/2y²-2x+1/2y+1/4=0两边乘以2得：10x²-6xy+y²-4x+y+1/2=0配方得：（3x-y-1/2)²+（x-

2x²=x²+x²所以(x²-2xy+y²)+(x²+2x+1)=0(x-y)²+(x+1)²=0平方大于等于0,相加等

1/(x^4)+4/(y^4)xy=1,所以y=1/x即y^4=1/（x^4）代入原式,得到1/(x^4)+4(x^4)再由重要不等式,得到1/(x^4)+4(x^4)≥2(根号)1/(x^4)·4(

x,y满足：|x-1|+（y+2）二次方=0那么x-1=0,y+2=0所以x=1,y=-2所以2x^2y-（5xy^2-4（xy^2-4分之3x二次方y）+x二次方y）+3xy二次方=2x^2y-(5

首先x3-y3=(x-y)(x2+xy+y2)其次x3-y3-3xy=1所以x3-y3=1+3xy=(x-y)(x2+xy+y2)x-y=(1+3xy)/(x2+xy+y2)=(1+3xy)/[(x-

将x^2+y^2+5/4=2x+y化为将x^2-2x+1+y^2-y+1/4=0即(x-1)^2+(y-1/2)^2=0上面的等式成立,则有x-1=0且y-1/2=0即x=1,y=1/2所以xy/(x

(X-1/2Y)方

x²+2xy-3y²=0(x+3y)(x-y)=0解得x=y或x=-3y又x,y为正数所以y=x；x=-3y舍(x²+xy+y²)/(x²-xy+y&

（x^2+xy+y^2）^2-4xy（x^2+y^2）=(x^2+y^2)^2+2xy(x^2+y^2)+x^2y^2-4xy(x^2+y^2)=(x^2+y^2)^2-2xy(x^2+y^2)+x^

第一题：设3^x=y,这里3^x表示3的x次方的意思那么原式变为y^2-8y-9=0,这个就简单了,解得y=-9或者y=1由于y=3^x,只能是3的整数次幂,所以y不能是-9,所以y=1那么3^x=1

∵x²+y²+6x-2y+10=0∴(x²+6x+9)+(y²-2y+1)=0即(x+3)²+(y-1)²=0由平方的非负性可得(x+3)&

2X方-4XY+4Y方-6X+9=0(x^2-4xy+4y^2)+(x^2-6x+9)=0(x-2y)^2+(x-3)^2=0所以有x-2y=0,x-3=0即有x=3,y=x/2=3/2x*根号8Y=

原式=2x²-4xy+2y²-7y²=(√2x-√2y)²-7y²=(√2x-√2y+√7y)(√2x-√2y-√7y)

4x方-4xy+y方-4x+2y-15=(2x-y)^2-2(2x-y)-15=(2x-y-5)*(2x-y+3)4x方y方-5x方y方-9y方题目弄错了吧,应该是这样的吧=4x^2y^2-5xy-9