x y=8,xy=8,求y倍根号下x分之y的值-搜答案-大师作文网

x^2+2y+√2y=17-4√2x^2+2y=17y=-4解得x=±5y=-4

x-4√xy-5y=0(√x+√y)(√x-4√y)=0√x=4√yx=16y(x+√xy-y)/(2x+√xy+3y)=(16y+4y-y)/(32y+4y+3y)=19y/39y=19/39

y=根号(x-8)+根号(8-x)+18,x-8≥0,8-x≥0x=8,y=18[(x+y)/(根号x+根号y)]-2xy/(x根号y-y根号x)=26/(2√2+3√2)-288/(8*3√2-18

呵呵,这题没什么技巧,可以直接算分母根号xy=1x+y=2根号2所以=2根号2-2分子x-根号xy=根号2+1-1=根号2分子分母同时除以根号2原式等于2-根号2

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

可得：x=2则y=8xy的平方根为：±4再问：步骤再答：因x-2,2-x都在根号下，所以有：x-2≥0解得：x≥2x-2≥0解得：x≤2,所以：x=2可得：x=2则y=8xy=16,：所以xy的平方根

x^2-4x+4=0得(x-2)^2=0x=2根号2y-根号y-2倍根号2+2=0(根号2-1)根号y=2（根号2-1）根号y=2,y=4根号xy=根号8=2倍根号2

X的平方-4X+4=0,x=2根号XY-根号Y-2倍根号X+2=0（根号Y-2）（根号2-1）=0y=4根号XY=2根号2

由√x(√x-√y)=√xy+3y,得x-2√xy-3y=0,(√x-3√y)(√x+√y)=0,上式要成立,就只能:(√x-3√y)=0或(√x+√y)=0,解得x=9y(x>0时)或x=y=0.你

x^2+2x+1+y-4√y+4=0,(x+1)^2+(√y-2)^2=0当且仅当x=-1,√y=2时等式成立,x=-1,y=4,√（-xy）=√4=2.

(√x-√y)²+4√(xy)=(√x+√y)²x=2/5y=8/5√(xy)=4/5√x+√y=√(2/5)+2√(2/5)=3√(2/5)(√x+√y)²/[x+√(

因为根号里的数不能为负数,所以X-2大于等于0,2－X大于等于0,所以X=2,Y=8,xy=16

x-8>=08-x>=0∴x=8把x=8代入Y=根号X-8+根号8-X在加18得y=18X-Y/根号X-根号y再减去2xy/x倍根号y-y倍的根号x=(√x+√y)-2√(xy)/(√x-√y)=(2

x+y-2倍根号xy=(根号x-根号y)^2=(22-1.6)^2=416.16根号x-根号y=22-1.6=20.4

x+5√(xy)-6y=0(√x+6√y)(√x-√y)=0√x=-6√y不合题意舍去,√x=√y即x=y……

x+2y+2xy=8≥2倍根号下2xy+2xy令2xy=t,t≥0,则2√t+t≤82√t≤8-tt≤8且4t≤64-16t+t²,t²-20t+64≥0,t≤4或t≥16所以0≤

因为x>0,y>0,所以将x-根号xy-2y=0因式分解得(根号x-2根号y)(根号x+根号y)=0所以根号x=2根号y,即x=4y后面请自己代入吧,我看不懂你的表述.不好意思了

根号2x-y-8+根号x+2y+1=0得到2x-y-8=0且x+2y+1=0所以x=3,y=-2xy=-6

原式提取公因式(/x+1)(/y)-2(/x+1)=(/x+1)(/y-2)=0,因此,/y-2=0,即y=4,x>=0.

解x^2+y^2+z^2=1x^2+(y/根2）^2+(y/根2)^2+z^2=12xy/根2+2yz/根2