Question

What is the cube root of -729a9b6

Answer 1

Answer:

-9a3b2

Step-by-step explanation:

Answer 2

ANSWER

$\sqrt[3]{- 729{a}^{9} {b}^{6} } = - 9 {a}^{3} {b}^{2}$

EXPLANATION

We want to find the cube root of

$- 729 {a}^{9} {b}^{6}$

We express this symbolically as:

$\sqrt[3]{- 729 {a}^{9} {b}^{6} }$

The expression under the radical called the radicand.

We need to express this radical in exponential form using the property,

${x}^{ \frac{m}{n} } = \sqrt[n]{ {x}^{m} }$

Applying this rule gives us:

$\sqrt[3]{- 729 {a}^{9} {b}^{6} } = ({- 729 {a}^{9} {b}^{6}})^{ \frac{1}{3} }$

$\sqrt[3]{- 729{a}^{9} {b}^{6} } = ({- {9}^{3} {a}^{9} {b}^{6}})^{ \frac{1}{3} }$

Recall that

$({a}^{m} )^{n} = {a}^{mn}$

We apply this rule on the RHS to get,

$\sqrt[3]{- 729{a}^{9} {b}^{6} } = ({- {9}^{3 \times { \frac{1}{3} } } {a}^{9 \times { \frac{1}{3} } } {b}^{6 \times { \frac{1}{3} } }})$

This simplifies to

$\sqrt[3]{- 729{a}^{9} {b}^{6} } = - 9 {a}^{3} {b}^{2}$