F.1數學

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

2007-11-29 20:39:29 補充：
3(k 5)-9k=2(3-4k)3k 15-9k=6-8k15-6=9k-8k-3k9=-2kk=-4.5

2007-12-03 09:37:32 補充：
1.求數式50-51 52-53 54-55 ...... 100-101 102的值 50-51=-152-53=-1 共有26對=26個-1 ......100-101=-126個-1=-26-26 102=76答案:762.一升降機由地下3層升至地下一層需3秒,問如果由第1層升至第39層需多少秒? 地下3層升至地下一層需3秒=升2層需3秒升1層=3/2秒第1層升至第39層=升38層38*3/2=57答案:57秒

2x/3 - 1/2 = x - 3/2
4x/6 - 3/6 = x - 3/2
(4x - 3)/6 = 6x/2 - 9/6
(4x - 3)/6 = (6x - 9)/6
(4x + 6x)/6 = (-9 - 3)/6
10x/6 = -12/6
5x/3 = -2
5x/3 x 3/5 = -2 x 3/5
x = 6/5

應該對的

2x/3 - 1/2 = x - 3/2
3/2 - 1/2 = x- 2x/3
(3-1)/2 =(3x-2x)/3
1 = x/3
x =3

通分sin,兩邊同乘6: 2x/ - 1/2 = x - 3/2
4x - 3 = 6x - 9
然後移項: 4x - 6x = -9 + 3
-2x = -6
得出答案: x = (-6)/(-2)
x = 3

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

2x/3 - 1/2 = x - 3/2
2/2 = x - 2x/3
1 = (3x - 2x)/3
x = 3