y-2分之√4-x √x-4,求XY
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2x-3y-1=0x-2y+2=02x-4y+4=0y-5=0y=55y=25x=82x-4=125y/(2x-4)=25/12
2x-y分之x+y=2,则2x-y=2(x+y)4x-2y分之x+y-4x+4y分之2x-y=2(2x-y)分之x+y-4(x+y)分之2x-y=4(x+y)分之x+y-4(x+y)分之2(x+y)=
x+y分之4x-2y-2x-y分之4x+4y=2(2x-y)/(x+y)-4(x+y)/(2x-y)=2*2-4*(1/2)=4-2=2
2倍根号2(把“根号y分之x+根号x分之y”整体处理一下.先平方,再开平方,值不变,再化简代值就很容易了.一定不要先去算X、Y的值!)
由4x+y-4x-6y+10=0得(4x-4x+1)+(y-6y+9)=0(2x-1)+(y-3)=0(2x-1)=0(y-3)=0x=1/2y=3代入所求算式即可求出结果(不好意思,看不清你的所求算
x+y=x-(x+3/2)^2+21/4=x-x^2-9/4-3x+21/4=-x^2-2x+12/4=-(x+1)^2+4因为-(x+1)^2
已知x,y满足√(2x-3y-1)+√(x-2y+2)=0,则√(2x-3y-1)=0,且√(x-2y+2)=0∴{2x-3y-1=0x-2y+2=0解得{x=8y=5∴2x-4分之5y=12分之25
y=x+√(2x+1)=(1/2)(2x+1)+√(2x+1)-1/2=(1/2)(√(2x+1)+1)²-1函数y=√(2x+1)值域为[0,+∞)所以y=√(2x+1)+1值域为[1,+
x²-2√3x+y²+2y+4=0(x-√3)²+(y+1)²=0∴x-√3=0y+1=0∴x=√3y=-1∴y/x=-√3/32、你的式子有些小问题,请核对好
y=√x^2-4+√4-x^2/(x-2)+3x^2-4>=04-x^2>=0x-2≠0解得:x=-2y=39x+8y=9×(-2)+8×3=6
∵x²+y²-4x-2y+5=0∴(x-2)²+(y-1)²=0∴x=2,y=1∴﹙(√x-√y)²+4√xy﹚/﹙x+√xy﹚=(√x+√y)
x²-4x+y²-y/2+65/16=0x²-4x+4+y²-y/2+1/16=0(x-2)²+(y-1/4)²=0x-2=y-1/4=0x
由已知条件可得:x-y=-4xy,(也就是在等式两边乘xy后整理,即可),代入所求的式子里分母为-4xy+7xy,即3xy;分子为-4xy-2xy,即-6xy,化简得-2
(3x-4y)÷(2x+y)=1/2所以2x+y=2(3x-4y)=6x-8y4x=9y所以x/y=9/4
y=(x^2+2x+4)/x=x+2+4/xx>0x=(√x)^24/x=(2/√x)^2=(√x)^2-4+(2/√x)^2+6=[(√x)-(2/√x)]^2+6
|x-3|+(4+y)²+√z+2=0则x=3,y=-4,z=-2所以2y+z分之3x=3x3/(-8-2)=-9/10
x/3-y/4=3x+2y==>4x-3y=36x+24y==>①32x=-27y==>x=-27y/32②(4x-3y)^2=(36x+24y)^2②==>16x^2+9y^2-24xy=1296x
①xy同非负时,2x-3√xy-2y=(2√x+√y)(√x-2√y)=0∴√x=2√y,x=4y②xy同负时,2x-3√xy-2y=[2√(-x)+√(-y)][√(-x)-2√(-y)]=0∴√(
利用柯西不等式(2/x+4/y)(x+y)≥(√2+2)²当且仅当x=2+4√2且y=4+2√2时取等∵2/x+4/y=1∴(x+y)≥(√2+2)²=6+4√2即(x+y)≥6+
原式等价于10(x+1)=5(y+3)=4(x+y)10(x+1)=5(y+3)可得2x-y=15(y+3)=4(x+y)可得4x-y=15解得x=7y=13x+2y+3=363x+2y+1=48两式