Friday, May 15, 2015

If 3^(x^2)/3^4x=1/81 then x=?

Since the bases of the exponetials from the left side are
matching, we'll apply quotient property and we'll subtract the superscripts, such
as:


3^(x^2)/3^4x = 3^(x^2 -
4x)


We'll create matching bases both sides, therefore we'll
write 81 = 3^4


3^(x^2 - 4x) =
1/3^4


We'll apply the negative power
rule:


3^(x^2 - 4x) =
3^(-4)


Since the bases of the exponetials are matching,
we'll equate the exponents:


x^2 - 4x =
-4


We'll add 4 both sides:


x^2
- 4x+ 4 = 0


We'll recognize the perfect square (x -
2)^2:


(x - 2)^2 = 0 => x1 = x2 =
2


The equation has two equal solutions: x1 =
x2 = 2.

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