Which expression is equivalent to [tex] \frac{5 y^3}{(5 y)^{-2}} [/tex]?

A. [tex] y^5 [/tex]

B. [tex] y^6 [/tex]

C. [tex] 125 y^3 [/tex]

D. [tex] 125 y^5 [/tex]



Answer :

To determine which expression is equivalent to [tex]\(\frac{5 y^3}{(5 y)^{-2}}\)[/tex], let's simplify the given expression step by step:

1. Original expression:
[tex]\[ \frac{5y^3}{(5y)^{-2}} \][/tex]

2. Simplify the denominator [tex]\((5y)^{-2}\)[/tex]:

The expression [tex]\((5y)^{-2}\)[/tex] can be rewritten using the property of exponents which states that [tex]\(a^{-n} = \frac{1}{a^n}\)[/tex]:
[tex]\[ (5y)^{-2} = \frac{1}{(5y)^2} \][/tex]

3. Calculate [tex]\((5y)^2\)[/tex]:

To square the term [tex]\(5y\)[/tex]:
[tex]\[ (5y)^2 = 5^2 \cdot y^2 = 25y^2 \][/tex]

Therefore:
[tex]\[ (5y)^{-2} = \frac{1}{25y^2} \][/tex]

4. Substitute the simplified denominator back into the original expression:
[tex]\[ \frac{5y^3}{\frac{1}{25y^2}} \][/tex]

5. Simplify the complex fraction:

To simplify [tex]\(\frac{5y^3}{\frac{1}{25y^2}}\)[/tex], you can multiply the numerator by the reciprocal of the denominator:
[tex]\[ \frac{5y^3}{\frac{1}{25y^2}} = 5y^3 \cdot 25y^2 \][/tex]

6. Multiply the terms:

To multiply [tex]\(5y^3\)[/tex] by [tex]\(25y^2\)[/tex]:
[tex]\[ 5 \cdot 25 \cdot y^3 \cdot y^2 \][/tex]
First, multiply the coefficients:
[tex]\[ 5 \cdot 25 = 125 \][/tex]
Then, use the property of exponents which states that when you multiply like bases, you add the exponents:
[tex]\[ y^3 \cdot y^2 = y^{3+2} = y^5 \][/tex]

7. Combine the results:

Therefore:
[tex]\[ 5 \cdot 25 \cdot y^3 \cdot y^2 = 125y^5 \][/tex]

Hence, the expression [tex]\(\frac{5y^3}{(5y)^{-2}}\)[/tex] simplifies to:

[tex]\[ 125 y^5 \][/tex]

So, the correct equivalent expression is:
[tex]\[ \boxed{125 y^5} \][/tex]