32000=100n^2+4000n
.
.
.
.
n=40
點計
問數 (32000=100n^2+4000n) 20點
2009-01-16 2:41 am
回答 (5)
2009-01-24 8:40 am
✔ 最佳答案
32000=100n^2+4000n32000=100(n^2+40n)
320=n^2+40n
n^2+40n-320=0
n={-40±√[(40)^2-4(1)(-320)]}/2(1)
n=[-20±√(1600+1280)]/2
n=6.83or n=-46.83
If
320000=100n^2+4000n
3200=n^2+40n
n^2+40n-3200=0
(n-40)(n+80)=0
n=40 or n=-80
所以你應該少了一個零
2009-01-18 5:38 pm
40*-80
=-3200
怎麼那麼多人都算錯了呢!?
=-3200
怎麼那麼多人都算錯了呢!?
2009-01-18 9:07 am
320000 = 100n^2+4000n 幫你加返個零
320000=100n^2+4000n <~~全部除100
320=n^2+40n <~~全部放係同一邊
0 = n^2+40n-320 <~~要用公式..如果你有學過既話
n -40 用n^2 同 -320 交叉相乘...
n +80 個答案要等於 40n
----------------------
-40n + 80n = 40n
(n- 40)(n+80)=0
n=40 or n= -80
320000=100n^2+4000n <~~全部除100
320=n^2+40n <~~全部放係同一邊
0 = n^2+40n-320 <~~要用公式..如果你有學過既話
n -40 用n^2 同 -320 交叉相乘...
n +80 個答案要等於 40n
----------------------
-40n + 80n = 40n
(n- 40)(n+80)=0
n=40 or n= -80
參考: 自己
2009-01-17 3:47 am
1)32000=100n^2+4000n
32000=100*40^2+4000*40
32000=160000+160000
32000=320000????????????????????????
你係咪少左個0?
_____________________________________________________
2)32000=100n^2+4000n
320=n^2+40n
n^2+40n-320=0
(n- 40)(n+80)=0
(n- 40)=0 or (n+80)=0
n=40 or n= -80
32000=100*40^2+4000*40
32000=160000+160000
32000=320000????????????????????????
你係咪少左個0?
_____________________________________________________
2)32000=100n^2+4000n
320=n^2+40n
n^2+40n-320=0
(n- 40)(n+80)=0
(n- 40)=0 or (n+80)=0
n=40 or n= -80
參考: need not to know
2009-01-16 3:37 am
32000=100n^2+4000n
320=n^2+40n
n^2+40n-320=0
(n- 40)(n+80)=0
(n- 40)=0 or (n+80)=0
n=40 or n= -80
320=n^2+40n
n^2+40n-320=0
(n- 40)(n+80)=0
(n- 40)=0 or (n+80)=0
n=40 or n= -80
收錄日期: 2021-04-21 12:40:27
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090115000051KK01235