3y+3x=9

3(x+y)-2(x-y)=114(x+y)+3(x-y)=93(x+y)-2(x-y)=114(x+y)+3(x-y)=93(x+y)-2(x-y)=114(x+y)+3(x-y)=93(x+y)-

4(x-y)-3(x-y)=95(x-y)+2(x-y)=114(x-y)-3(x-y)=95(x-y)+2(x-y)=114(x-y)-3(x-y)=95(x-y)+2(x-y)=11打错了吧,这样

求函数f（x,y）=x×x×x－y×y×y+3×x×x+3×y×y－9x的极值求函数f（x,y）=x×x×x－y×y×y+3×x×x+3×y×y－9x的极值求函数f（x,y）=x×x×x－y×y×y+

（x+y-5)*（x+y-5)+（x-y+3)=0x*x-y*y（x+y-5)*（x+y-5)+（x-y+3)=0x*x-y*y（x+y-5)*（x+y-5)+（x-y+3)=0x*x-y*y这是什么

已知:3x-5y=0,求x/y,x-y/y,x-y/x已知:3x-5y=0,求x/y,x-y/y,x-y/x已知:3x-5y=0,求x/y,x-y/y,x-y/x3x-5y=03x=5y→x/y=5/

9y=3x-(x-1),4(x+y)-(2x+4)=8y9y=3x-(x-1),4(x+y)-(2x+4)=8y9y=3x-(x-1),4(x+y)-(2x+4)=8y解9y=3x-(x-1)2x-9

5x=3y,(2x+y)的平方=5x(x+y)+95x=3y,(2x+y)的平方=5x(x+y)+95x=3y,(2x+y)的平方=5x(x+y)+95x=3y,x=3y/5(2x+y)的平方=5x(

3x-2y=9x-3y=2x+y=5x+2y=3y=x2x+y=83x-2y=9x-3y=2x+y=5x+2y=3y=x2x+y=83x-2y=9x-3y=2x+y=5x+2y=3y=x2x+y=8解

3y=2xy/3=x/212/x=9/yy/x=?y/x=?x/y=?3y=2xy/3=x/212/x=9/yy/x=?y/x=?x/y=?3y=2xy/3=x/212/x=9/yy/x=?y/x=?

根据3（x+y)-2(x-y)=11,4(x+y)+3(x-y)=9可得出x+y=,x-y=根据3（x+y)-2(x-y)=11,4(x+y)+3(x-y)=9可得出x+y=,x-y=根据3（x+y)

已知2x-y/x+2y=3,求2(2x-y)/x+2y-9(x+2y)/2x-y+3的值.已知2x-y/x+2y=3,求2(2x-y)/x+2y-9(x+2y)/2x-y+3的值.已知2x-y/x+2

推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做.推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做.推倒公式:(x+y)(x*x-3x+y*y)=x

(x+y)(x-y)+(x-y)平方-(x-y)(3x-y)其中x=-2y=3分之一(x+y)(x-y)+(x-y)平方-(x-y)(3x-y)其中x=-2y=3分之一(x+y)(x-y)+(x-y)

x-y=3,xy=9,x+y=?x-y=3,xy=9,x+y=?x-y=3,xy=9,x+y=?(x-y)^2=x^2+y^2-2xy=9(x+y)^2=x^2+y^2+2xy=9+4xy=45x+y

(x-y)(x-2y)+(x+2y)(x-3y)-2(x-3y)(x-4y)=(x-y)(x-2y)+(x+2y)(x-3y)-2(x-3y)(x-4y)=(x-y)(x-2y)+(x+2y)(x-3

Y=x+37x+5y=9Y=x+37x+5y=9Y=x+37x+5y=9把Y=x+3中的Y带到7x+5y=9式子中7X+5（X+3）=912X+15=912X=—6X=—0.5将X=—0.5代入Y=x

y-x=37x+5y=-9y-x=37x+5y=-9y-x=37x+5y=-9y-x=3(1)7x+5y=-9(2)(1)*7+(2)12y=12y=1x=-2y-x=35y-5x=157x+5y=-

y=x+37x+5y=9y=x+37x+5y=9y=x+37x+5y=9y=x+3代入7x+5y=9得7x+5x+15=9x=-0.5代入y=x+3得y=2.5∴﹛x=-0.5,y=2.5是原方程组的

2x+3y=9x+y=202x+3y=9x+y=202x+3y=9x+y=20把x+y=20转换成x=20-y代入到前面的式子得出2（20-y）+3y=940+y=9y=-31代入x+y=20得出x=

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)已知x-y/x+y=3,求代数式5(x-y)/x+y