Question 1118936
.
<pre>
I read your post (your formulas) in this way:



        If  {{{x^y}}} = a  and  {{{x^(4y)-4}}} = 77,  find the value of  a.



Then   {{{x^(4y)-4}}} = {{{a^4-4}}},  and the given equation is


    {{{a^4-4}}} = 77  ====>  {{{a^4}}} = 77 + 4 = 81.


It implies that "a" may have four possible values:


    - two real values  a= 3  and  a= -3,


    - and two imaginary values  a= 3i  and  a= - 3i.
</pre>