第一题:知道3a+b/2a-b=5 ,求 4a-2b/3a+b + 3a+b/6a-3b 的值第二题:知x;y;z=3;4;7 且2x-y+z=18 求x+2y-z的值需要过程——————————————————————————————————————
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![第一题:知道3a+b/2a-b=5 ,求 4a-2b/3a+b + 3a+b/6a-3b 的值第二题:知x;y;z=3;4;7 且2x-y+z=18 求x+2y-z的值需要过程——————————————————————————————————————](/uploads/image/z/5381675-35-5.jpg?t=%E7%AC%AC%E4%B8%80%E9%A2%98%EF%BC%9A%E7%9F%A5%E9%81%933a%2Bb%2F2a-b%3D5+%2C%E6%B1%82+4a-2b%2F3a%2Bb+%EF%BC%8B+3a%2Bb%2F6a-3b+%E7%9A%84%E5%80%BC%E7%AC%AC%E4%BA%8C%E9%A2%98%EF%BC%9A%E7%9F%A5x%3By%3Bz%3D3%3B4%3B7+%E4%B8%942x-y%2Bz%3D18+%E6%B1%82x%2B2y-z%E7%9A%84%E5%80%BC%E9%9C%80%E8%A6%81%E8%BF%87%E7%A8%8B%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94%E2%80%94)
第一题:知道3a+b/2a-b=5 ,求 4a-2b/3a+b + 3a+b/6a-3b 的值第二题:知x;y;z=3;4;7 且2x-y+z=18 求x+2y-z的值需要过程——————————————————————————————————————
第一题:知道3a+b/2a-b=5 ,求 4a-2b/3a+b + 3a+b/6a-3b 的值
第二题:知x;y;z=3;4;7 且2x-y+z=18 求x+2y-z的值
需要过程————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————
OK就给分咯
第一题:知道3a+b/2a-b=5 ,求 4a-2b/3a+b + 3a+b/6a-3b 的值第二题:知x;y;z=3;4;7 且2x-y+z=18 求x+2y-z的值需要过程——————————————————————————————————————
1、
(3a+b)/(2a-b)=5
3a+b=10a-5b
7a=6b
a=6b/7
(4a-2b)/(3a+b)+(3a+b)/(6a-3b)
=(4*6b/7-2b)/(3*6b/7+b)+(3*6b/7+b)/(6*6b/7-3b)
=(10b/7)/(25b/7)+(25b/7)/(15b/7)
=2/5+5/3
=31/15
2、
x;y;z=3;4;7
x/3=y/4=z/7
令a=x/3=y/4=z/7
x=3a
y=4a
z=7a
2x-y+z=18
6a-4a+7a=18
9a=18
a=2
x+2y-z
=3a+8a-7a
=4a
=8
把3、4、5分别代入2x-y+z,发现2*3-4+7=9
所以x=6,y=8,z=14
然后再计算x+2y-z,得8.
3a+b/2a-b=5,2a-b/3a+b=1/5
4a-2b/3a+b + 3a+b/6a-3b =2/5+5/3=31/15
知x;y;z=3;4;7,令x=3a,y=4a,z=7a
2x-y+z=6a-4a+7a=9a=18
a=2
x=6,y=8,z=14
x+2y-z=8
4a-2b/3a+b + 3a+b/6a-3b =2/(3a+b/2a-b)+(3a+b/2a-b)/3=31/15
2。解得x=6,y=8,z=14,则x+2y-z=8