I need to factor the following please help x^2-8x+20=0?
回答 (7)
2008-09-25 7:48 am
✔ 最佳答案
x = 10
2008-09-25 7:49 am
This can't be factored using real coefficients. Use the quadratic formula
x = (16 +/- sqrt(64 - 80))/2
= (16 +/- sqrt( -16))/2
= 8 + 2i or 8 - 2i
and the factorization becomes
(x - 8 - 2i)(x - 8 + 2i) = 0
= = = = = Edited to add: = = = = =
Maybe I should just retire today. For some reason I took the quad formula to be {- 2b +/- etc} and my answer is wrong. As others have pointed out, the roots are 4+/- 2i.
x = (16 +/- sqrt(64 - 80))/2
= (16 +/- sqrt( -16))/2
= 8 + 2i or 8 - 2i
and the factorization becomes
(x - 8 - 2i)(x - 8 + 2i) = 0
= = = = = Edited to add: = = = = =
Maybe I should just retire today. For some reason I took the quad formula to be {- 2b +/- etc} and my answer is wrong. As others have pointed out, the roots are 4+/- 2i.
2008-09-25 7:48 am
USE THE FORMULA
B^2 = -b +/- sqrt gshadghasgd
B^2 = -b +/- sqrt gshadghasgd
2008-09-25 11:40 am
x^2 - 8x + 20 = 0 (<== cannot be factored)
x = [-b ±√(b^2 - 4ac)]/2a (<== quadratic formula)
a = 1
b = -8
c = 20
x = [8 ±√(64 - 80)]/2
x = [8 ±√-16]/2 (imaginary number)
(no real roots)
x = [-b ±√(b^2 - 4ac)]/2a (<== quadratic formula)
a = 1
b = -8
c = 20
x = [8 ±√(64 - 80)]/2
x = [8 ±√-16]/2 (imaginary number)
(no real roots)
2008-09-25 7:58 am
The answers are imaginary numbers:
4+2i or 4-2i
You have to use the quadratic formula:
http://www.1728.com/quadratc.htm
Try this site
4+2i or 4-2i
You have to use the quadratic formula:
http://www.1728.com/quadratc.htm
Try this site
2008-09-25 7:56 am
Equating the equation=X^2 + (a+b)X +ab =X^2-8X+20=0
X=+4+ or -(16-20)^1/2 you get (X-4-2i)(X-4+2i)=0,where
i=(-1)^1/2
X=+4+ or -(16-20)^1/2 you get (X-4-2i)(X-4+2i)=0,where
i=(-1)^1/2
2008-09-25 7:55 am
i think u wrote the problem wrong
its probably x^2-8x-20=0
but if that is the actual problem, then there is no solution
its probably x^2-8x-20=0
but if that is the actual problem, then there is no solution
收錄日期: 2021-05-01 11:15:29
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080924234034AAiNVxB