Question 1014353
<pre>

You should not have typed 9^4x-12 =6,561, for that does not
mean the same as this

{{{9^(4x-12)}}}{{{""=""}}}{{{6561}}}

You should have written it this way:

9^(4x-12) = 6561

When algebra has to be written all on one line and there is no way
you write either exponents above the line, or denominators below the
line, you must always enclose each expression in parentheses to show 
where numerators, denominators and exponents begin and end.
Otherwise what you write may be misinterpreted. 

Anyway, to find out if your answer is correct, check it and see:

{{{9^("4(4)"-12)}}}{{{""=""}}}{{{6561}}}

Do the operations on the left (do the exponent first)
and see if you get

{{{6561}}}{{{""=""}}}{{{6561}}}

If you do, then you'll know 4 is the correct answer.
Otherwise you'll know you made a mistake.

Edwin</pre>