我想問下:
1 (2m-3b)-(-5b+9n)
answer係2m+2b-9n
而唔係2m+2b+9n?
2 (3k-2ky)-(1-4y+8ky)
answer係 3k-10ky-4y-1
而唔係 3k+6y-4y-1?
HELP!!~~唔明點解呀!!!
急!!!F.1 maths!!!
2007-10-05 2:22 am
回答 (4)
2007-10-05 2:43 am
✔ 最佳答案
(2m-3b)-(-5b+9n)=2m-3b+5b-9n
ans.2m+2b-9n
Why(2m-3b)-(-5b+9n)==2m-3b+5b-9n?
because--=+,-5bchange to 5b,-+=-,9n change to -9n
(3k-2ky)-(1-4y+8ky)
=3k-2ky-1+4y-8ky
=3k-10ky+4y-1
2007-10-05 2:32 am
1. (2m-3b)-(-5b+9n)
=2m+2b-9n
係因為負號和負號就係=正號
2 (3k-2ky)-(1-4y+8ky)
= 3k-10ky-4y-1
係因為負正得負
口訣:負正得負.正負得負.正正得正.負負得正.
=2m+2b-9n
係因為負號和負號就係=正號
2 (3k-2ky)-(1-4y+8ky)
= 3k-10ky-4y-1
係因為負正得負
口訣:負正得負.正負得負.正正得正.負負得正.
參考: me
2007-10-05 2:30 am
(2m-3b)-(-5b+9n)
=2m - 3b +5b - 9n 個"-"乘左入去
=2m +2b -9n
(3k-2ky)-(1-4y+8ky)
=3k- 2ky -1 + 4y - 8ky
=3k -10ky +4y -1
=2m - 3b +5b - 9n 個"-"乘左入去
=2m +2b -9n
(3k-2ky)-(1-4y+8ky)
=3k- 2ky -1 + 4y - 8ky
=3k -10ky +4y -1
2007-10-05 2:28 am
1 (2m-3b)-(-5b+9n)
=2m-3b+5b-9m
=-7m+2b
2 (3k-2ky)-(1-4y+8ky)
=3k+4y-2ky-8ky-1
=6ky+3k+4y-1
2007-10-04 18:29:15 補充：
- - = ++ - = -
=2m-3b+5b-9m
=-7m+2b
2 (3k-2ky)-(1-4y+8ky)
=3k+4y-2ky-8ky-1
=6ky+3k+4y-1
2007-10-04 18:29:15 補充：
- - = ++ - = -
收錄日期: 2021-04-13 17:43:18
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071004000051KK02594