ＭＡＴＨＳ

#1. 解6y-3(5-y)=21
6y-15+3y=21
9y=36
y=4
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#2. 解(8y-9)+(15-2y)=6-18
6y+6=-12
6y=-18
y=-3
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#3. 解4(3m除５)-2m-8=0
[4(3m除５)-2m-8]*5=0*5
12m-10m-40=0
2m=40
m=20
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#4. 如果正方形的2條鄰邊分別長x cm 和(2x-3)cm 求正方形的周界
正方形每邊長度皆相等
x=2x-3
x=3
正方形的周界
=4*邊長
=4*3
=12cm

1. 解6y-3(5-y)=21

6y - 15 - 3y = 21
3y = 36
y = 12

2. 解(8y-9)+(15-2y)=6-18

8y - 9 + 15 - 2y = -12
6y + 6 = -12
y + 1 = - 2
y = -3

3. 解4(3m除５)-2m-8=0

4 (3m / 5) - 2m - 8 = 0

12m / 5 - 2m - 8 = 0

12m - 10m = 40
2m = 40
m = 20

2007-08-13 17:07:21 補充：
4. 如果正方形的2條鄰邊分別長x cm 和(2x-3)cm 求正方形的周界 x=2x-3 x=3 周界 ： 3 x 4 = 12