求代数式y分之1 2x的值-搜答案-拍题作业网

x+3y分之2x-y等于2(2x-y)/(x+3y)=2代数式x+3y分之4x-2y减去2x-y分之4x+12y=2(2x-y)/(x+3y)-4(x+3y)/(2x-y)=2*2-4*(1/2)=4

(2x-y)/(x+3y)=2所以原式=2(2x-y)/(x+3y)-3(x+4y)/(2x-y)=2(2x-y)/(x+3y)-3/[(2x-y)/(x+3y)]=2×2-3/2=5/2

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

能把问题说得明白点么是不是二分之x的方加y的方这是一个整体?然后再减xy?

由已知条件可得,3x-3y=2.得,3x=3y+2代数式4x+5y+2-x+2y=3x+7y+2,将3x=3y+2代入得,10y+4即代数式的值为10y+4没办法,只能是这样表示了哦!

x=1/3y=1/2x-(x+y）+（x+2y)-(x+3y)+...-(x+13y)=6y-13y=-7y=-7/2=-3.5

3x²+xy-2y²=0(x+y)(3x-2y)=0x=-y,或3x=2yy/x=-1,或3/2x/y-y/x-(x²+y²)/(xy)=x/y-y/x-x/y

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

1.33又五分之一2.213.13分之124.a=_-3___时,它有最大值为_3___

解原式=2(x-y)/(x+y)-(x+y)/3(x-y)=6(x-y)(x-y)/[3(x+y)(x-y)]-(x+y)x+y)/[3(x-y)(x+y)]=5(x-y)(x-y)/[(x+y)(x

x+3y分之4x-2y-2x-y分之4x+12y=2(2x-y)/(x+3y)-4(x+3y)/(2x-y)=2*2-4*1/2=4-2=2

因为X+2/X-Y=2所以X=2Y+2将X=2Y+2代入X+Y/3（X-Y）-（X-Y）/2（X+Y）=（3Y+2）/3（2Y+2-Y）-（2Y+2-Y）/2（3Y+2）接下来自己算

设3分之x等于4分之y等于7分之z等于=kx=3ky=4kz=7k代数式y分之3x+y+z=(3*3k+4k+7k)/4k=20k/4k=5

x^2+y^2+5/4=2x+y(x-1)^2+(y-1/2)^2=0x=1,y=1/2xy/(x+y)=1*(1/2)/(1+1/2)=1/3

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

因为x＋y/2=3x＋4y/5=1,所以x＋y=2,3x＋4y=5所以解方程组得x=3,带入x＋5y＋6/3x－y＋1,得4/11

(3x+y-6)/(4x-y-8)=[3x+y-3(x-2y)]/[4x-y-4(x-2y)]=5y/7y=5/57

解；(x/y-y/x)=(x²-y²)/xy(y分之x-x分之y)除以(x+y)=(x-y)/xy=0∴x=y

负11