（4）3分之1-2x=7分之3x+1在-3

要过程啊！！！

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1/3 - 2x = (3x+1)/7 - 3
1 - 6x = （9x+3)/配念派7 -9
7 - 42x = 9x +3 -63
51x =67
x=67/高谈51

或
(1-2x)/3=(3x+1)/7 - 3
1-2x = (9x+3)/培贺7 -9
7-14x=9x+3-63
23x=67
x=67/23

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