兩條方程題目

1) 5s-20%=8.3
5s-0.2=8.3
5s=8.3-0.2
5s=8.1
s=1.62

2) 2/5*(r+75%)=1/2
0.4*(r+0.75)=0.5
0.4r+3=0.5
0.4r=0.5-3
0.4r=-2.5
r=-6.25

2007-05-18 22:10:11 補充：
sorry...sorry, 計錯數呀!!!! .

2007-05-18 22:10:31 補充：
sorry...sorry, 計錯數呀!!!! .

2007-05-18 22:10:49 補充：
2) 2/5*(r 75%)=1/20.4*(r 0.75)=0.50.4r 0.3=0.50.4r=0.5-0.30.4r=0.2r=1/2or2/5*(r 75%)=1/22r/5 2/5*3/4=1/22r/5 3/10=1/22r=5(1/2-3/10)2r=5/2-15/102r=25/10-15/102r=10/10r=5/10r=1/2個人認為第2個解法有D麻煩...=.="

2007-05-18 22:14:10 補充：
其實可以再簡單D=.="2/5*(r+75%)=1/2r+75%=(1/2)/(2/5)r+3/4=1/2*5/2r+3/4=5/4r=5/4-3/4r=2/4r=1/2

第一條第三行應該係
5s=8.3+0.2
吾係減

1) 5s-20%=8.3
5s-0.2=8.3
5s=8.5
s=1.7

2)2/5(r+75%)=1/2
0.4(r+0.75)=0.5
0.4r+0.3=0.5
0.4r=0.2
r=0.5

1)
5s-20%=8.3
5s=8.3+20/100
5s=8.5
s=8.5/5
s=1.7

2)
2/5*(r+75%)=1/2
r+75%=1/2*5/2
r+75%=5/4
r=5/4-75%
r=1/2

1) 5s-20%=8.3
5s-0.2=8.3
5s=8.5
s=1.7

2) 2/5(r+75%)=1/2
2/5(r+75%)=1/2
2/5r+3/10=1/2
10(2/5r+3/10)=1/2(10)
4r+3=5
4r=2
r=1/2

1)
5s-20%=8.3
5s-0.2=8.3
5s=8.3+0.2
s=8.5/5
=1.7
2)
2/5 x (r+75%)=1/2
0.4 x (r+0.75)=0.5
r+0.75=0.5/0.4
r=1.25-0.75
=0.5

1)5s-20%=8.3
5s=8.3+20%
5s=8.5
s=1.7
2) 2/5(r+75%)=1/2
0.4x(r+0.75)=0.5
(r+0.75)=0.5/0.4
r=1.25-0.75
r=0.5

1)5s-20%=8.3
5s=8.3+20%
5s=8.5
s=1.7
2) 2/5乘(r+75%)=1/2
0.4x(r+0.75)=0.5
(r+0.75)=0.5/0.4
r=1.25-0.75
r=0.5

1)
5s-20%=8.3
5s=8.3+20/100
5s=8.5
s=8.5/5
s=1.7

2)
2/5*(r+75%)=1/2
r+75%=1/2*5/2
r+75%=5/4
r=5/4-75%
r=1/2

1) 5s-20%=8.3
5s-0.2=8.3
5s=8.5
s=1.7
2) 2/5乘(r+75%)=1/2
2/5(r+75%)=1/2
2/5r+3/10=1/2
10(2/5r+3/10)=1/2(10)
4r+3=5
4r=2
r=1/2