不懂的數學問題

2012-11-17 5:50 am
(3b-1) (b+4) (5-b) = ???

回答 (5)

2012-11-17 6:52 am
✔ 最佳答案
(3b-1) (b+4) (5-b)
= (3b^2 + 12b -b -4)(5-b) 先處理頭及中間的括號
= (3b^2 + 11b - 4)(5-b)
= 15b^2 -3b^3 + 55b - 11b^2 - 20 + 4b 小心做加減
= -3b^3 + 4b^2 + 59b - 20 調埋位, 完成
參考: myself
2012-11-17 5:42 pm
(3b-1)(b+4)(5-b)
=(4b-4)(5-b)
=20b-4b
=16b
2012-11-17 6:11 am
-3b^3+4b^2+59b-20


^ = 幾多次方

2012-11-16 22:12:55 補充:
yts****** ( 小學級 5 級 )
回答時間: 2012-11-16 22:09:49

.........................

wrong gee 16b................

2012-11-16 22:13:25 補充:
-3b3+4b2+15b-20 also wrong
2012-11-17 6:09 am
(3b-1)(b+4)(5-b)
=(4b-4)(5-b)
=20b-4b
=16b


I hope i can help you:))
參考: me
2012-11-17 6:08 am
-3b3+4b2+15b-20
*字母後面果D系次方


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