唔該幫下手教下我．．．．係點計．．．要教我同比答案= =

2007-08-20 6:07 pm

(一).化簡下列各代數式....
2 2
(a) 4y -2y+7-2y+3y +5y-2

(b) a+2b+3c+4a-6b-2c

(c) 2ab+3a-2b+4a-6b+5ab
幫下手計....最好就教埋我點計...唔該幫下忙喇...

更新1:

呀........對唔住... 2 2 (a) 4y -2y+7-2y+3y +5y-2 ↑↑↑↑ 上面有2個2既....果個錯左...應該一個2係4y,一個係2係3y,2←姐係2次,姐係4y既2次...3y既2次...明未?

更新2:

2 2 ｅ兩個２．．係4y的既2次方,一個就3y既,姐係3y既2次方....明未呀- -"我打得唔好- -所以就變成咁.....明未呀?教我做喇

回答 (1)

miu127melody

2007-08-20 7:19 pm

✔ 最佳答案

a) (4y)^2-2y+7-2y+(3y)^2+5y-2
=8y^2+9y^2-2y-2y+5y+7-2
=17y^2+y-2

b) a+2b+3c+4a-6b-2c
=a+4a+2b-6b+3c-2c
=5a-4b+c

c) 2ab+3a-2b+4a-6b+5ab
=2ab+5ab+3a+4a-2b-6b
=7ab+7a-8b

解釋下a題，^2 = 2次方
(4y)^2 = 4y既2次方，8y^2 = 8y square(即8乘y既2次方)
唔知你明唔明呢？

2007-08-20 11:21:35 補充：
sorry，a題計錯左更正如下：a) (4y)^2-2y+7-2y+(3y)^2+5y-2=16y^2+9y^2-2y-2y+5y+7-2=25y^2+y+5

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