maths 功課

1. 2x = 3(1-x) - (x-1)
2x = 3 - 3x - x + 1
2x = 4 - 4x
6x = 4
x = 4/6
x = 2/3 //

2. 28y = 2[ 16 - 4(1-y) ]
28y = 2( 16 - 4 + 4y )
28y = 32 - 8 + 8y
20y = 24
y = 24/20
y = 6/5 //

3. (2n-5)÷3 = (n-10)÷9
2n - 5 = ( n-10 )÷3
3(2n - 5) = n - 10
6n - 15 = n - 10
5n = 5
n = 1 //

1. 2x=3(1-x)-(x-1)
2x=3-3x-x+1
2x=4-4x
6x=4
x=4/6
x=2/3

2. 28y=2[16-4(1-y)]
28y=2[16-4+4y]
28y=2[12+4y]
28y=24+8y
20y=24
y=1.2

3. (2n-5)÷3=(n-10)÷9
3(2n-5)=(n-10)
6n-15=n-10
5n=5
n=1

maths 功課 :


1. 2x = 3(1-x) - (x-1)
2x = 3 - 3x - x + 1
2x = 4 - 4x
6x = 4
x = 4/6
x = 2/3 //

2. 28y = 2[ 16 - 4(1-y) ]
28y = 2( 16 - 4 + 4y )
28y = 32 - 8 + 8y
20y = 24
y = 24/20
y = 6/5 //

3. (2n-5)÷3 = (n-10)÷9
2n - 5 = ( n-10 )÷3
3(2n - 5) = n - 10
6n - 15 = n - 10
5n = 5
n = 1 //

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

2x = 3-3x -x +1
2x + 4x = 4
6x = 4
x= 2/3

2. 28y = 2[16-4(1-y)]

28y = 2[16 - 4 + 4y]
28y = 2(12+ 4y)
28y = 24 + 8y
28y - 8y = 24
20y = 24
y = 6/5

3. (2n-5)÷3=(n-10)÷9

2n - 5 = (n-10)÷9 x 3
2n - 5 = (n - 10) ÷3
(2n - 5) x 3 = n - 10
6n - 15 = n - 10
5n = 5
n=1

2007-02-21 16:24:46 補充：
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2x=3-3x-x+1
2x=4x+4
2x-4x=4
-2x=4
x=-2