3(x+y)—4(x—y)=4 { (x+y)/2+(x—y)/6=1
来源：学生作业帮助网 编辑：六六作业网 时间：2024/11/25 04:24:28
3(x+y)—4(x—y)=4{(x+y)/2+(x—y)/6=13(x+y)—4(x—y)=4{(x+y)/2+(x—y)/6=1 3(x+y)—4(x—y)=4{(x+y)/2+(x—y
3(x+y)—4(x—y)=4 { (x+y)/2+(x—y)/6=1
3(x+y)—4(x—y)=4 { (x+y)/2+(x—y)/6=1
3(x+y)—4(x—y)=4 { (x+y)/2+(x—y)/6=1
令x+y=a,x-y=b
3a-4b=4③
a/2+b/6=1
3a+b=6④
④-③，得
5b=2
b=2/5
a=28/15
x=(2/5+28/15)÷2=17/15
b=(28/15-2/5)÷2=11/15
x+y=-4,怎么样求二分之一【x+y】—4【X-y】+3【x-y】减三分之二【x+y】+【x—y】的值
已知X,Y满足x平方+y平方—4x+6y+13=0,求代数式（3x+y）的平方-3（3x-y)(x+y)-(x-3y)(x+3y)
3(x+y)—4(x—y)=4 { (x+y)/2+(x—y)/6=1
2(x-y)/3—x+y/4=1 6(x+y)—4(2x-y)=16
3(x+y)—4(x-y)=4,(x+y/2)+(x-y/6)=1.解方程组
(x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)=
（y-x)+x(x-y)^3-(y-x)^4 因式分解
已知;2y-x= —3,求 [4y(2x - y) - 2x(2x - y)]÷（2x-y）的值.
如果X.Y满足X平方+Y平方—4X+1=0求3/X的最大值 Y-X最小值 X平方+Y平方的最大值
—2x+5(x+2y)—(x—3y) 3x+2(y-x)-(-x-4y) (x-2y)-(y-3—2x+5(x+2y)—(x—3y) 3x+2(y-x)-(-x-4y)(x-2y)-(y-3x)
（3x-y)(y+3x)-(4x-3y)（4x+3y)=?
（5x+3y)(3y-5x)-(4x-y)(4y+x)=
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
{3(x+y)+3(y+x)=1,3(x+y)+4(y-x)=-1
2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15
x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20
{(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20
4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6