小六升中一數學問題

1)
8x+4/2-(3x-2)
=8x+2-3x+2
=5x+4


2)
5(a-1)/2-4(a+1)/2
=(15a-15-8a-8)/6
=(7a-3)/6


3)
(2m+5/2)-(m-1/4)
=2m+5/2-m+1/4
=m+10/4+1/4
=m+11/4


4)
6(2a+7/3)+4(3a-5/2)
=12a+14+12a-10
=24a+4
=4(6a+1)

1. 8x+4/2 - (3x-2)

=8x+4/2-3x+2

=8x-3x+4/2+2

=5x+2+2

=5x+4

2. 5(a-1)/2 - 4(a+1)/3

=6X{5(a-1)/2} - {4(a+1)/3}X6

=3[5(a-1)]-[4(a+1)X2]

=3(5a-5)-2(4a+4)

=15a-15-8a-8

=15a-8a-15-8

=7a-7

3. (2m+5/2) - (m-1/4)

=2m+5/2-m+1/4

=2m-m+5/2+1/4

=m+10/4+1/4

=m+11/4

=m+2右3/4

2010-09-03 22:03:20 補充：
6(2a+7/3)+4(3a-5/2)
=12a+14+12a-10
=24a+4
=4(6a+1)

1)
(8x + 4) / 2 - (3x - 2)

= 4x + 2 - 3x + 2

= x + 4

2)
5(a - 1) / 2 - 4(a + 1) / 3

= [15(a - 1) - 8(a + 1)] / 6

= (7a - 23) / 6

3)
(2m + 5) / 2 - (m - 1) / 4

= [2(2m + 5) - (m - 1)] / 4

= (3m + 11) / 4

4)
6 * (2a + 7) / 3 + 4 * (3a - 5) / 2

= 2(2a + 7) + 2(3a - 5)

= 10a + 4