數學 F.1 方程(3) 20分

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1. (1/3+1)y=4
4/3y=4
4/3yx3/4=4x3/4
y=3

2 .y/2-y/3=5
3/6y-2/6y=5
1/6y=5
1/6yx6/1=5x6/1
y=30

3. 2y/5+y/2=3
4y/10+5y/10=3
9y/10=3
9y/10x10/9=3x10/9
y=10/3

4. 2-y/4=y/2
2-y/4+y/4=y/2+y/4
2x4/3=3y/4x4/3
8/3=y

1)
y/3+y = 4
y/3 = 4-y
y = (4-y)3
y = 12-3y
y+3y = 12
4y = 12
y = 3

2)
y/2-y/3 = 5

3y/6 - 2y/6 = 5

y/6 = 5

y = 30

3)
2y/5+y/2 = 3
4y/10 +5y/10 = 3
9y/10 = 3
9y = 30
y = 9/30
y = 3/10

4) 2-y/4 = y/2
2-y = (y/2)4
2- y = 2y
2 = 2y+y
3y = 2
y = 2/3

1. y/3+y=4
3(y+3y)=3*4
4y=12
y=3

2. y/2-y/3=5
2*3(y/2-y/3)=2*3*5
3y-2y=30
y=30

3. 2y/5+y/2=3
2*5(2y/5+y/2)=2*5*3
4y=5y=30
y=10/3

4. 2-y/4=y/2
4*(2-y/4)=4*y/2
8-y=2y
8=3y
y=8/3
y=2 2/3

1) y/3+y = 4
y/3 = 4-y
y = (4-y)3
y = 12-3y
y+3y = 12
4y = 12
y = 3

2) y/2-y/3 = 5
3y/6 - 2y/6 = 5
y/6 = 5
y = 30

3) 2y/5+y/2 = 3
4y/10 +5y/10 = 3
9y/10 = 3
9y = 30
y = 9/30
y = 3/10

4) 2-y/4 = y/2
2-y = (y/2)4
2- y = 2y
2 = 2y+y
3y = 2
y = 2/3

1) y/3+y = 4
y/3 = 4-y
y = (4-y)3
y = 12-3y
y+3y = 12
4y = 12
y = 3

2) y/2-y/3 = 5
3y/6 - 2y/6 = 5
y/6 = 5
y = 30

3) 2y/5+y/2 = 3
4y/10 +5y/10 = 3
9y/10 = 3
9y = 30
y = 9/30
y = 3/10

4) 2-y/4 = y/2
2-y = (y/2)4
2- y = 2y
2 = 2y+y
3y = 2
y = 2/3

2008-03-22 21:28:56 補充：
sori 打錯野..

3)9y = 30
y = 30/9
y = 10/3