Question 281925
{{{log(4, (x)) = 2log(4, (3))}}}
With the variable in the argument of a logarithm you will often want to transform the equation into one of the following forms:
log(expression) = other-expression
or
log(expression) = log(other-expression)<br>
The only difference between your equation and the second form is the 2 in front of the log on the right side. We can't get rid of the 2 by dividing both sides because then the left side would not be right. But we can use the property of logarithms, {{{q*log(a, (p)) = log(a, (p^q))}}}, to move the coefficient into the argument as an exponent. Using this property on your equation we get:
{{{log(4, (x)) = log(4, (3^2))}}}
or
{{{log(4, (x)) = log(4, (9))}}}
and we have the second form. With this form we have two logarithms that are equal. The next step is based on some simple logic. If the base 4 log of x is the same as the base 4 log of 9 then x must be the same as 9. In other "words":
x = 9