Question 876668
<pre>
Here's an alternate way.  Slightly different:

{{{matrix(2,1,"",


(x-4)^(2/3))}}}{{{matrix(2,1,"",""="")}}}{{{matrix(2,1,"",16)}}}

We want to make the exponent {{{2/3}}} become a whole
number. So we raise both sides to the 3 power. That is,
we cube both sides:

{{{((x-4)^(2/3))^3}}}{{{""=""}}}{{{16^3}}}

{{{(x-4)^2}}}{{{""=""}}}{{{4096}}}

Use the principle of square roots:

{{{x-4}}}{{{""=""}}}{{{"" +- sqrt(4096)}}}

{{{x-4}}}{{{""=""}}}{{{"" +- 64}}}

x-4 = 64;      x-4 = -64
  x = 68;        x = -68

Edwin</pre>