Select the correct answer.

If \( x \) and \( y \) are positive real numbers, which expression is equivalent to the expression below?

[tex]\[
\left(125 x^4 y^{\frac{3}{2}}\right)^{\frac{1}{3}} \div (x y)^{\frac{1}{2}}
\][/tex]

A. \( 5 x^{\frac{11}{6}} \)

B. \( 5 x^{\frac{5}{8}} y \)

C. \( 5 x^{\frac{5}{6}} \)

D. [tex]\( 5 x^{\frac{7}{2}} y \)[/tex]



Answer :

To solve the given expression \(\left(125 x^4 y^{\frac{3}{2}}\right)^{\frac{1}{3}} \div (x y)^{\frac{1}{2}}\):

1. Simplify the numerator \(\left(125 x^4 y^{\frac{3}{2}}\right)^{\frac{1}{3}}\):

Apply the power of a power rule \((a^m)^n = a^{mn}\):

[tex]\[ \left(125 x^4 y^{\frac{3}{2}}\right)^{\frac{1}{3}} = 125^{\frac{1}{3}} \cdot (x^4)^{\frac{1}{3}} \cdot \left(y^{\frac{3}{2}}\right)^{\frac{1}{3}} \][/tex]

We know that \(125 = 5^3\), so:

[tex]\[ 125^{\frac{1}{3}} = 5 \][/tex]

Simplify the exponents:

[tex]\[ (x^4)^{\frac{1}{3}} = x^{\frac{4}{3}} \][/tex]
[tex]\[ \left(y^{\frac{3}{2}}\right)^{\frac{1}{3}} = y^{\frac{3}{2} \cdot \frac{1}{3}} = y^{\frac{1}{2}} \][/tex]

Combining these, the numerator simplifies to:

[tex]\[ 5 x^{\frac{4}{3}} y^{\frac{1}{2}} \][/tex]

2. Simplify the denominator \((x y)^{\frac{1}{2}}\):

Apply the power of a product rule \((ab)^m = a^m b^m\):

[tex]\[ (x y)^{\frac{1}{2}} = x^{\frac{1}{2}} y^{\frac{1}{2}} \][/tex]

3. Divide the simplified numerator by the simplified denominator:

[tex]\[ \frac{5 x^{\frac{4}{3}} y^{\frac{1}{2}}}{x^{\frac{1}{2}} y^{\frac{1}{2}}} \][/tex]

Use the quotient rule \(a^{m}/a^{n} = a^{m-n}\) to reduce the powers of \(x\) and \(y\):

[tex]\[ 5 \cdot \frac{x^{\frac{4}{3}}}{x^{\frac{1}{2}}} \cdot \frac{y^{\frac{1}{2}}}{y^{\frac{1}{2}}} \][/tex]

Simplify the \(y\)-terms:

[tex]\[ \frac{y^{\frac{1}{2}}}{y^{\frac{1}{2}}} = 1 \][/tex]

Simplify the \(x\)-terms:

[tex]\[ x^{\frac{4}{3} - \frac{1}{2}} = x^{\frac{4}{3} - \frac{1}{2}} = x^{\frac{8}{6} - \frac{3}{6}} = x^{\frac{5}{6}} \][/tex]

Combines everything:

[tex]\[ 5 \cdot x^{\frac{5}{6}} \][/tex]

Therefore, the expression is equivalent to [tex]\(\boxed{5 x^{\frac{5}{6}}}\)[/tex].