12(2y - 1)(y + 1)
can i write it as.........
12(2y + 1)(y - 1)
it is the ans for...::
24y(square) + 12y - 12
top urgent...thz a lot
simple maths 12(2y-1)(y+1)
2007-06-22 6:51 am
回答 (3)
2007-06-22 7:26 am
✔ 最佳答案
NOwhen you are trying to convert the negative sign, you should be reminded about the following:
(2y - 1) = - (-2y + 1) = -(-2y) - (+1)
therefore, 12(2y - 1)(y + 1)
=12( -2y + 1) (-y - 1)
=12(2y^2 + y -1)
=24y^2 + 12y - 12
But not 12(2y + 1)(y - 1)
參考: meself =]
2007-06-22 10:35 pm
Definitely NOT!
If you really want to change it, it will become:
= -12 (-2y + 1) (-y + 1)
= -12 (1 - 2y) (1-y)
It should be:
12 (2y - 1) (y + 1)
= (24y - 12) (y + 1)
= 24y^2 + 24y - 12y - 12
= 24y^2 + 12y - 12
If you really want to change it, it will become:
= -12 (-2y + 1) (-y + 1)
= -12 (1 - 2y) (1-y)
It should be:
12 (2y - 1) (y + 1)
= (24y - 12) (y + 1)
= 24y^2 + 24y - 12y - 12
= 24y^2 + 12y - 12
2007-06-22 6:57 am
12(2y - 1)(y + 1) CANNOT write as 12(2y + 1)(y - 1)
because
12(2y-1)(y+1) = 12(2y^2 +y-1) but
12(2y + 1)(y - 1)= 12(2y^2 -y-1)
so
12(2y-1)(y+1) = 12(2y^2 +y-1) = 24y^2 +12y -12
because
12(2y-1)(y+1) = 12(2y^2 +y-1) but
12(2y + 1)(y - 1)= 12(2y^2 -y-1)
so
12(2y-1)(y+1) = 12(2y^2 +y-1) = 24y^2 +12y -12
收錄日期: 2021-04-12 21:58:51
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070621000051KK05063