方程式 help~help

3(c-1) = 2(c-1) + 2
3(c-1) - 2(c-1) = 2
(c-1) = 2
c = 3
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9(x+3) + 12 = 7(x+5)
9(x+3) - 7(x+5) = -12
2(x+5) = -12
(x+5) = -6
x = -11


2007-10-09 18:41:27 補充：
眼大睇過龍, 3 睇錯左為 5, sorry9(x+3) + 12 = 7(x+5)9x + 27 + 12 = 7x + 359x + 39 = 7x + 352x + 39 = 352x = -4x = -2咁有心做, 請投我一票啦, 唔該

3(c-1)=2(c-1)+2
3c-3=2c-2+2
3c-3=2c
3c-2c=3
c=3


9(x+3)+12=7(x+5)
9X+27+12=7X+35
9x+4=7x
7x-9x=4
-2x=4
x=-2

3(C-1)=2(C-1)+2
3C-3=2C-2+2
3C-3=2C
3C/2C=3
C=3


9(X+3)+12=7(X+5)
9X+27+12=7X+35
9X+39=7X+35
9X+39-35=7X
9X+4=7X
4=7X-9X
4=-2X
X=-2

1)3(c-1)=2(c-1)+2
3c-3=2c-2+2
3c=2c+3
c=3

2)9(X+3)+12=7(X+5)
9X+27+12=7X+35
9X+39-35=7X
9X+4=7X
9X-7X=-4
2X=-4
X=-2

3(c-1) = 2(c-1) +2
3c-3 = 2c-2+2
3c-3 = 2c
3c-2c = 3
c=3


9(x+3)+12 = 7(x+5)
9x+27+12 = 7x + 35
9x + 39 = 7x +35
9x-7x=35-39
2x = -4
x = - 2