Question 660385
If you are allowed to use a calculator
{{{a^3 = 729}}}
{{{a = (729)^(1/3)}}}
{{{a = 9}}}

{{{c^6 = a^3}}}
{{{c^2 = a}}}
{{{c^2 = 9}}}
{{{c = sqrt(9)}}}
{{{c = 3}}} or {{{c = -3}}}

If you are not allowed to use a calculator, then start by factoring 729 into prime factors

{{{729 = 3 * 243}}}
{{{729 = 3 * 3 * 81}}} etc etc
{{{729 = 3 * 3 * 3 * 3 * 3 * 3}}}
And use that info to solve the given questions