Question 135430: Hi. I'm am required to find x in this equation: = . My teacher told me answer is +1 or -1. I do know the formula - Change of Base Law - to solve the equation, but the problem is, I do not know how to apply the formula due to the square root of 5 as the base of the equation.
I've tried by using the formula to change :
5-4x = 2-x
-3x = -3
x = 1
However, I don't know how to find -1. Please teach me the correct method. Thanks.
(By the way, the answer is +1 with the + sign begin underlined. I hope you understand what I mean. And is this answer the same as 1 and -1? Thanks.) Answer by Earlsdon(6294) (Show Source):
Change the base of the second logarithm to that of the first using:
So, we end up with:
Applying the power rule to the right side:
Add 4x to both sides.
Subtract 5 from both sides.
Factor the right side.
The answer can be read as: x = + or - 1