3(x+y)—4(x-y)=4,(x+y/2)+(x-y/6)=1.解方程组

3(x+y)—4(x-y)=4,(x+y/2)+(x-y/6)=1.解方程组
3(x+y)—4(x-y)=4,(x+y/2)+(x-y/6)=1.解方程组

3(x+y)—4(x-y)=4,(x+y/2)+(x-y/6)=1.解方程组
化简得: 3(x+y)-4(x-y)=4
3x+3y-4x+4y=4
-x+7y=4
-x=4-7y
x=7y-4
(x+y/2)+(x-y/6)=1
2x+y/3=1
2(7y-4)+y/3=1
14y-8+y/3=1
42y-24+y=3
43y=27
y=27/43
x=7y-4=7×27/43-4=17/43

45+985

既然出了这个题，你就应该学到了这个知识，再来问，真是很不可理解，上课时打酱油去啦！！！这么简单的问题

3X+3Y-4X+4Y=4
7Y-X=4
X=7Y-4 ①
将①代入X+Y\2+X-Y\6=1得
7Y-4+Y\2+7Y-4-Y\6=1
化简得43Y=27
Y=27\43 ②
将②代入①得
X=17\43

3(x+y)—4(x-y)=4,(x+y/2)+(x-y/6)=1 转化得7y-x=4,2x+y/3=1 解方程组得x= 17/43 ，y= 27/43

3(x+y)-4(x-y)=4
3x+3y-4x+4y=4
-x+7y=4
-x=4-7y
x=7y-4
(x+y/2)+(x-y/6)=1
2x+y/3=1
...

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3(x+y)-4(x-y)=4
3x+3y-4x+4y=4
-x+7y=4
-x=4-7y
x=7y-4
(x+y/2)+(x-y/6)=1
2x+y/3=1
2(7y-4)+y/3=1
14y-8+y/3=1
42y-24+y=3
43y=27
y=27/43
x=7y-4=7×27/43-4=17/43

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