作业帮解x+y/3+x-y/2=2① 4(x+y)-7(x-y)=-2 ②过程………………
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解x+y/3+x-y/2=2① 4(x+y)-7(x-y)=-2 ②过程………………
解x+y/3+x-y/2=2① 4(x+y)-7(x-y)=-2 ②
过程………………
解x+y/3+x-y/2=2① 4(x+y)-7(x-y)=-2 ②过程………………
答：
(x+y)/3+(x-y)/3=2
4(x+y)-7(x-y)=-2
设a=x+y,b=x-y,方程组化为：
a/3+b/3=2…………（1）
4a-7b=-2…………（2）
(1)*12-(2)得：
4a-4a+4b+7b=24+2
11b=26
b=26/11
代入（2）得：
4a-182/11=-2
4a=(182-22)/11
4a=160/11
a=40/11
所以：
a=x+y=40/11
b=x-y=26/11
两式相加：2x=66/11=6,x=3
代入a得：a=3+y=40/11
解得：y=7/11
所以：x=3,y=7/11
(x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)=
x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2
解二元一次方程组：3(x+y)-4(x-y)=4,x+y/2+x-y/6+1x+y/2+x-y/6+1=1
2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15
3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2
（x+y）/2- x-y/2=6 3(x+y)=4(x-y)
x+y/3+x-y/2=6 4(x+y)-2(x-y)=40
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
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
3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9
4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5
已知2y-x=-3,求[4y(2x-y)-2x(2x-y)]/(2x-y
x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=?
3(x+y)-2(x-y)=4; 3(x+y)+2x-2y=8 3(x+y)-2(x-y)=4; 3(x+y)+2x-2y=8 解方程组