Question 937581
{{{((1/sqrt(8))^(-2/3))-81^0.75}}} ........since {{{0.75=75/100=3/4}}}, we have


{{{(1/(1/(sqrt(8))^(2/3)))-81^(3/4)}}}


{{{sqrt(8)^(2/3)-81^(3/4)}}}


{{{root(3,(sqrt(8))^2)-root(4,81^3)}}} .......since {{{81^3=(9^2)^3=9^6=(3^2)^6=3^12}}}, we have


{{{root(3,8)-root(4,3^12)}}} .........since {{{3^12=3^3*3^3*3^3*3^3=(3^3)^4}}}, we have


{{{root(3,3^3)-root(4,(3^3)^4)}}}


{{{3-3^3}}}


{{{3-9}}}


{{{-6}}}