1元2次方程1條

👨🏻‍🏫 學術台數學

用戶249867

2009-08-31 3:11 am

5^(2x)=10(5^x)+25=0

更新1:

我唔明點由2個等於变成一個等於...

更新2:

If a and b are the roots of the equation 2x^2-5x+4=0, find the values of a. 2a+2b b. (a-1)(b-1) c. a^2+b^2 d. (a-b^2)

回答 (2)

myisland8132

2009-08-31 3:39 am

✔ 最佳答案

Let y=5^x, then the equation becomes
y^2-10y+25=0
(y-5)^2=0
y=5
5^x=5
x=1

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NgThn

2009-08-31 4:29 am

設y =5^x
y^2=10y+25=0
y^2-10y-25=0
(y-5)(y-5)=0
y=5
5^x=5
x=1

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