Convert to Radical Form -(16/81)^(3/4)

$- {(\frac{16}{81})}^{\frac{3}{4}}$

Apply the product rule to $\frac{16}{81}$ .

$- \frac{16^{\frac{3}{4}}}{81^{\frac{3}{4}}}$

Simplify the numerator.

Rewrite $16$ as $2^{4}$ .

$- \frac{{(2^{4})}^{\frac{3}{4}}}{81^{\frac{3}{4}}}$

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$- \frac{2^{4 (\frac{3}{4})}}{81^{\frac{3}{4}}}$

Cancel the common factor of $4$ .

Cancel the common factor.

$- \frac{2^{4 (\frac{3}{4})}}{81^{\frac{3}{4}}}$

Rewrite the expression.

$- \frac{2^{3}}{81^{\frac{3}{4}}}$

Raise $2$ to the power of $3$ .

$- \frac{8}{81^{\frac{3}{4}}}$

Simplify the denominator.

Rewrite $81$ as $3^{4}$ .

$- \frac{8}{{(3^{4})}^{\frac{3}{4}}}$

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$- \frac{8}{3^{4 (\frac{3}{4})}}$

Cancel the common factor of $4$ .

Cancel the common factor.

$- \frac{8}{3^{4 (\frac{3}{4})}}$

Rewrite the expression.

$- \frac{8}{3^{3}}$

Raise $3$ to the power of $3$ .

$- \frac{8}{27}$