x - 3 ........ 3
------ = ---------
3 ............. x + 5
How do i do this?
2008-05-03 6:43 pm
回答 (4)
2008-05-03 6:50 pm
✔ 最佳答案
(x-3)/3 = 3/(x+5)Cross-multiply:
(x-3)(x+5) = 3∙3
Expand:
x²+2x-15 = 9
x²+2x-24 = 0
Factor to find the roots:
x²+2x-24 =(x-4)(x+6) = 0
x = 4
x = -6
2008-05-03 6:48 pm
cross multiply
3x3=(x-3)(x+5)
9 = x^2 +2x - 15
-9 -9
0 = x^2 + 2x - 24
(x+6) (x-4)
factors are -6 and +4
3x3=(x-3)(x+5)
9 = x^2 +2x - 15
-9 -9
0 = x^2 + 2x - 24
(x+6) (x-4)
factors are -6 and +4
2008-05-03 6:47 pm
(x - 3)/3 = 3/(x + 5)
x - 3 = 3(3)/(x + 5)
x - 3 = 9/(x + 5)
(x - 3)(x + 5) = 9
x^2 - 3x + 5x - 15 = 9
x^2 + 2x - 15 - 9 = 0
x^2 + 2x - 24 = 0
(x + 6)(x - 4) = 0
x + 6 = 0
x = -6
x - 4 = 0
x = 4
â´ x = -6 , 4
x - 3 = 3(3)/(x + 5)
x - 3 = 9/(x + 5)
(x - 3)(x + 5) = 9
x^2 - 3x + 5x - 15 = 9
x^2 + 2x - 15 - 9 = 0
x^2 + 2x - 24 = 0
(x + 6)(x - 4) = 0
x + 6 = 0
x = -6
x - 4 = 0
x = 4
â´ x = -6 , 4
2008-05-03 6:47 pm
(x-3)/3 = 3/(x+5)
cross multiply:
3 x 3 = (x-3) x (x+5)
9= x^2 + 2x -15
x^2 + 2x - 24 = 0
factor:
(x+6)(x-4) = 0
x= -6, 4
Hope this helped! ;P
cross multiply:
3 x 3 = (x-3) x (x+5)
9= x^2 + 2x -15
x^2 + 2x - 24 = 0
factor:
(x+6)(x-4) = 0
x= -6, 4
Hope this helped! ;P
收錄日期: 2021-05-01 10:29:33
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080503104333AAIHZln