求ｘ的值
120 = x ( 5x - 1 )
數學問題1條(代數)(須列式)(10分)
2007-10-26 9:28 pm
回答 (5)
2007-10-26 9:39 pm
✔ 最佳答案
120=5x^2 - x5x^2-x-120=0
(5x+24) (x-5)=0
所以
5x+24=0 or x-5=0
x=-24/5 or x=5
參考: MEME
2007-10-27 6:33 am
1.
120 = x ( 5x - 1 )
120 = 5x->2 - x
5x->2 - x - 120 = 0
x = [1± √(1 - 4 X 5 X -120)] / (2 X 5)
x = 5
120 = x ( 5x - 1 )
120 = 5x->2 - x
5x->2 - x - 120 = 0
x = [1± √(1 - 4 X 5 X -120)] / (2 X 5)
x = 5
參考: me
2007-10-26 9:56 pm
120 = x ( 5x - 1 )
=> 120 = 5x^2 - x
=> 5x^2 - x - 120 = 0
=> (5x + 24)(x - 5) = 0
=> x = -24/5 or 5
=> 120 = 5x^2 - x
=> 5x^2 - x - 120 = 0
=> (5x + 24)(x - 5) = 0
=> x = -24/5 or 5
2007-10-26 9:46 pm
120 = x ( 5x - 1 )
120 = 5x^2 - x
5x^2 - x - 120 = 0
x = [1± √(1 - 4 X 5 X -120)] / (2 X 5)
x = 5 or -4.8
x = your unknown 未知數
^2 = square 2次方
X = multiple sign 乘號
120 = 5x^2 - x
5x^2 - x - 120 = 0
x = [1± √(1 - 4 X 5 X -120)] / (2 X 5)
x = 5 or -4.8
x = your unknown 未知數
^2 = square 2次方
X = multiple sign 乘號
參考: quatratic formula
2007-10-26 9:41 pm
120=X(5X-1)
120 (5X-1)
------= --------
5 5
24=2X-1
24 2X-1
---- = --------
2 2
12=X-1
12+1=X-1+1
13=X
x=13
120 (5X-1)
------= --------
5 5
24=2X-1
24 2X-1
---- = --------
2 2
12=X-1
12+1=X-1+1
13=X
x=13
收錄日期: 2021-04-13 14:10:36
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071026000051KK01240