Select the correct answer.

Which expression is equivalent to [tex]\sqrt[3]{56 x^7 y^5}[/tex], if [tex]x \neq 0[/tex] and [tex]y \neq 0[/tex]?

A. [tex]2 x^2 y \sqrt[3]{7 x y^2}[/tex]
B. [tex]8 x y \sqrt[3]{7 x^4 y^2}[/tex]
C. [tex]8 x^2 y \sqrt[3]{7 x y^2}[/tex]
D. [tex]2 x^4 y^2 \sqrt[3]{7}[/tex]



Answer :

To simplify the expression [tex]\(\sqrt[3]{56 x^7 y^5}\)[/tex], let's work through the steps systematically:

1. Factor 56 into a product including a perfect cube:
[tex]\[ 56 = 8 \times 7 \][/tex]
Note that [tex]\(8\)[/tex] is a perfect cube since [tex]\(8 = 2^3\)[/tex].

2. Factor [tex]\(x^7\)[/tex] into a product involving perfect cubes:
[tex]\[ x^7 = (x^6) \cdot x = (x^2)^3 \cdot x \][/tex]
Here, [tex]\( (x^2)^3 \)[/tex] is a perfect cube.

3. Factor [tex]\(y^5\)[/tex] into a product involving perfect cubes:
[tex]\[ y^5 = (y^3) \cdot y^2 = y \cdot (y^2)^3 \][/tex]
Similarly, [tex]\((y^2)^3\)[/tex] is a perfect cube.

4. Combine all terms under the cube root, factoring out perfect cubes:
[tex]\[ \sqrt[3]{56 x^7 y^5} = \sqrt[3]{8 \cdot 7 \cdot (x^2)^3 \cdot x \cdot y \cdot (y^2)^3} \][/tex]

5. Extract the perfect cubes from under the cube root:
[tex]\[ = \sqrt[3]{2^3 \cdot 7 \cdot (x^2)^3 \cdot x \cdot y \cdot (y^2)^3} = \sqrt[3]{2^3} \cdot \sqrt[3]{(x^2)^3} \cdot \sqrt[3]{(y^2)^3} \cdot \sqrt[3]{7xy} = 2 \cdot x^2 \cdot y \cdot \sqrt[3]{7xy^2} \][/tex]

So, the simplified form of [tex]\(\sqrt[3]{56 x^7 y^5}\)[/tex] is:
[tex]\[ 2 x^2 y \sqrt[3]{7 x y^2} \][/tex]

Hence, the correct answer is:
[tex]\[ \boxed{A} \][/tex]