3xsquared - 21=0 solve for x?
回答 (8)
2008-12-05 4:22 pm
✔ 最佳答案
3x^2 - 21 = 03x^2 = 21
x^2 = 7
x = sqrt(7)
2008-12-05 4:28 pm
3x^2 - 21 = 0
First you need to move -21 to the other side of = but remember when moving you have to change sign to positive
3x^2 = 21
Then you need to get 3 away from the x in order to do that 3 needs to be divided be 21 since 3 and x are being multiplied
x^2 = 21/3
x^2 = 7
First you need to move -21 to the other side of = but remember when moving you have to change sign to positive
3x^2 = 21
Then you need to get 3 away from the x in order to do that 3 needs to be divided be 21 since 3 and x are being multiplied
x^2 = 21/3
x^2 = 7
2008-12-05 4:27 pm
Transpose -21 to the other side that's why it is now +21.
Divide both sides by 3, leaving x^2=7.
Square both sides resulting to x=sqrt7.
Divide both sides by 3, leaving x^2=7.
Square both sides resulting to x=sqrt7.
參考: My mind told me that. :)
2008-12-05 4:27 pm
3x^2 - 21 = 0
3x^2 = 21
x^2 = 21/2
x^2 = 7
x = 屉7
3x^2 = 21
x^2 = 21/2
x^2 = 7
x = 屉7
2008-12-05 4:25 pm
3 x ² = 21
x ² = 7
x = ± â7
x ² = 7
x = ± â7
2008-12-05 4:24 pm
Factor out the 3
3(x^2 - 7) = 0
x^2 - 7 = 0
x^2 = 7
x = sqrt(7) x = -sqrt(7)
3(x^2 - 7) = 0
x^2 - 7 = 0
x^2 = 7
x = sqrt(7) x = -sqrt(7)
參考: Longtime college math teacher
http://www.CharlesAshbacher.net
2008-12-05 4:23 pm
3x^2-21=0
x^2-7=0
x=square root of 7 and -square root 7
x^2-7=0
x=square root of 7 and -square root 7
2008-12-05 4:23 pm
3x²-21 = 0
3x² = 21
x² = 7
x = ±â7 â ± 2.646
3x² = 21
x² = 7
x = ±â7 â ± 2.646
收錄日期: 2021-05-01 11:36:25
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20081205081924AASQsoD