Question 1209401
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Reduce the given equation to the standard form quadratic equation

    a^2 - a - 1 = 0.


Solve it using the quadratic formula.


The roots are  {{{a[1]}}} = {{{(1 + sqrt(5))/2}}}  and  {{{a[2]}}} = {{{(1 - sqrt(5))/2}}}.


Raise each root to degree 3, performing routine arithmetic.


You will obtain two values/expressions for "a^3".
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Boldly go forward following my instructions.