maths 中一

(s+1) / 3 + (s-1) /7 = -6

7(s+1) / 21 + 3(s-1) / 21 = -6

(7s+7+3s-3) /21 =-6

(10s+4) / 21 =-6

(10s+4) /21 * 21 = -6*21

10s+4 = -126

10s+4-4 = -126 -4

10s = -130

s = -13

s/3+1+s/7-1=-6
7s/21+3s/21=-6
10s/21=-6
10s=-126
s=-12.6

(s+1) / 3 + (s-1) /7 = -6

(7s+7)/ 21 +( 3s-3) / 21 = -6

(7s+7+3s-3) /21 =-6

(10s+4) / 21 =-6

(10s+4) /21 x 21 = -6x21

10s+4 = -126

10s+4-4 = -126 -4

10s = -130

s = -13

2006-10-21 13:03:02 補充：
Sorry. That is wrong.(s+1) / 3 + (s-1) /7 = -6(7s+7)/ 21 +( 3s-3) / 21 = -6(7s+7+3s-3) /21 =-6(10s+4) / 21 =-6(10s+4) /21 x 21 = -6x2110s+4 = -12610s+4-4 = -126 -410s=-122s=12.2

(s + 1)/3 + ( s-1)/7 = -6
(s + 1)7 + (s - 1)3 = -6
7s + 7 + 3s - 3 = -6
10s + 4 = -6
10s = -10
s = -1

(s+1)/3+(s-1)/7=-6
[(s+1)x7]/(3x7)+[(s-1)x3]/(7x3)=-6
(7s+7+7s-7)/21=-6
(7s+7s)/21=-6
14s/21=-6
2s/3=-6
s=-6x(3/2)
s=-9

2006-10-21 11:38:06 補充：
sorry is this↓(s+1)/3+(s-1)/7=-6(3s-3+7s+7)/21=-6(10s+4)/21=-610s+4=-6x2110s=-122s=-12.2