Question 1014465
<pre>

You can use either log or ln.  You will get the
same answer either way. 

{{{matrix(2,3,"","","",
3^sqrt(21x),""="",12^sqrt(21))}}}

{{{matrix(2,3,"","","",
log((3^sqrt(21x))),""="",log((12^sqrt(21))))}}}

{{{sqrt(21x)log((3))}}}{{{""=""}}}{{{sqrt(21)log((12))}}}

{{{sqrt(21)sqrt(x)log((3))}}}{{{""=""}}}{{{sqrt(21)log((12))}}}

Divide both sides by {{{sqrt(21)}}}

{{{sqrt(x)log((3))}}}{{{""=""}}}{{{log((12))}}}

Divide both sides by log(3)

{{{sqrt(x)}}}{{{""=""}}}{{{log((12))/log((3))}}}

Square both sides:

{{{x}}}{{{""=""}}}{{{(log((12))/log((3)))^2}}}

Approximately:

{{{x}}}{{{""=""}}}{{{5.11600843}}}

Edwin</pre>