Y=3√(4-x) 4√(x-3)

4x²+y²-4x-6y+10=0,4x²-4x+1+y²-6y+9=0(2x-1)²+(y-3)²=0x=1/2y=3[2x／3*√(9x

3(x+y)+3(y-x)=1(1)3(x+y)+4(y-x)=-1(2)(2)-(1)得y-x=-2(3)代入（1）3（x+y)-6=1x+y=7/3=>x=7/3－y又由（3）得x=y+2y+2=

由(1)得3x+3y+2x-2y=365x+y=36(3)由(2)得4x+4y-3x+3y=-20x+7y=-20(4)(3)×7-(4)得34x=272∴x=8把x=8代入(3)得y=-4∴x=8y

{(x+y)/2+(x-y)/3=63(x+y)+2(x-y)=36(1)4(x+y)-3(x-y)=-20(2)由（1）*3+(2)*2得9(x+y)+6(x-y)+8(x+y)-6(x-y)=36

因4x²+y²-4x-6y+10=0所以4x²-4x+1+y²-6y+9=0(2x-1)²+(y-3)²=0所以2x-1=0,y-3=0x=

即(4x²-4x+1)+(y²-6y+9)=0(2x-1)²+(y-3)²=0所以2x-1=y-3=0x=1/2,y=3原式=2x√x+√(xy)-x√x-5√

4x^2+y^2-4x-6y+10=0.配方得(2x-1)^2+(y-3)^2=0,∴2x-1=0,y-3=0,解得x=1/2,y=3.∴(2/3)√(9x)+y^2√(x/y^3)-[x√(1/x)

化简得：-x+7y=11①7x+3y=27②①式×7得：-7x+49y=77③②+③得：52y=104∴y=2代入①得：x=3∴x=3,y=2再问：亲，是代入法哦！再答：代入法①式得3x+3y-4x+

绝对值和开根号都是大于等于0的,他两相加等于0说明都是0,分别算就行了,xy都是0

求y=√([(x-1)(x-2)]/[(x-3)(x-4)])的导数吧,用对数求导法两边求对数lny=1/2[ln(x-1)+ln(x-2)-ln(x-3)-ln(x-4)]两边对x求导,记住y不是自

第二个方程是不是写错了2/（x+y）+3/（x-y）=6是这样吗

(6x√y/x+3/y*√xy^3)-(4x√x/y+√36xy)=6√（xy)+3√（xy)-4x/y*√（xy)-6√（xy)=(3-4x/y)√(xy)x=3/2,y=27时,原式=（3-2/9

Y=√(2X+4)-√(X+3)=(2X+4)^0.5-(X+3)^0.5=0.5×[(2X+4)^(0.5-1)]×(2X+4)'-0.5×[(X+3)^(0.5-1)]×(X+3)'=0.5×[(

x、y是有理数,并且x、y满足等式x的平方+2y+y√3=17-4√3→(x的平方+2y)+y√3=(17)-4√3→y√3=-4√3→y=-4(x的平方+2y)=17(x的平方-8)=17x的平方=

3(x+y)-4(x-y)=4(x+y)/2+(x-y)/6=1令a=x+y,b=x-y3a-4b=4(1)a/2+b/6=1则3a+b=6(2)(2)-(1)5b=2b=2/5a=(6-b)/3=2

（5x+3y)(3y-5x)-(4x-y)(4y+x)=(3y)^2-(5x)^2-(4x^2+15xy-4y^2)=9y^2-25x^2-4x^2-15xy+4y^2=13y^2-15xy-29x^

(x²+2y)+√3y=17-4√3∵x,y是有理数∴x²+2y=17,y=-4解得x=±5,y=-4x+y=1或-9

前面的式子配方后（x-2）^2+(y-1)^2=0得出x=2,y=1后面的式子看不清楚只要把x,y代进去就可以了

完整设1/(x+y)=a,1/(x-y)=b原方程组可变为4a+6b=39b-a=1a=9b-136b-4+6b=3b=1/6,a=1/2x+y=2x-y=6所以原方程组的解为：x=4,y=-2

我把方法告诉你,最后的答案你自己做吧,很容易.(x+y)(x+2y)(x+3y)(x+4y)=-40(x+y)（x+4y）(x+2y)(x+3y）=-40(x^2+5yx+44)(x^2+5yx+66