Wednesday, July 15, 2015

What is the solution of the equation log 4 (2x-20) = 1

Before solving the equation, we have to impose constraints
of existance of logarithm
function.


2x-20>0


We'll
add 20 both sides:


2x>20We'll divide by
2:


x>10


So, for the
logarithms to exist, the values of x have to be in the interval (10,
+inf.)


Now, we'll solve the
equation:


2x-20= 4^1


2x-20 =
4


We'll add 20 both sides:


2x
= 20+4


2x = 24


We'll divide by
2:


x =
12


The solution is admissible because the
value belongs to the interval (10,+inf.)

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