Select the correct answer.

Which expression is equivalent to the given expression?

[tex]\[ \frac{\left(a b^2\right)^3}{b^5} \][/tex]

A. [tex]\[ \frac{a^3}{b} \][/tex]

B. [tex]\[ a^3 b \][/tex]

C. [tex]\[ a^3 \][/tex]

D. [tex]\[ \frac{a^4}{b} \][/tex]



Answer :

Sure, let's solve the given expression step by step.

We need to simplify the expression
[tex]\[ \frac{(a \cdot b^2)^3}{b^5} \][/tex]

### Step 1: Expand the numerator
First, we expand the expression in the numerator:
[tex]\[ (a \cdot b^2)^3 \][/tex]

To do this, we apply the power of a product rule, which states that [tex]\((xy)^n = x^n \cdot y^n\)[/tex]. Thus:
[tex]\[ (a \cdot b^2)^3 = a^3 \cdot (b^2)^3 \][/tex]

### Step 2: Simplify the exponents of [tex]\(b\)[/tex]
Next, we simplify [tex]\((b^2)^3\)[/tex] using the power of a power rule, which states that [tex]\((x^m)^n = x^{m \cdot n}\)[/tex]:
[tex]\[ (b^2)^3 = b^{2 \cdot 3} = b^6 \][/tex]

So the expression now becomes:
[tex]\[ a^3 \cdot b^6 \][/tex]

### Step 3: Substitute back into the original expression
We substitute [tex]\(a^3 \cdot b^6\)[/tex] back into the original fraction:
[tex]\[ \frac{a^3 \cdot b^6}{b^5} \][/tex]

### Step 4: Simplify the fraction
To simplify the fraction, we use the quotient rule for exponents which states [tex]\(\frac{x^m}{x^n} = x^{m-n}\)[/tex]:
[tex]\[ \frac{a^3 \cdot b^6}{b^5} = a^3 \cdot b^{6-5} = a^3 \cdot b^1 = a^3 \cdot b \][/tex]

So, the simplified form of the given expression [tex]\(\frac{(a b^2)^3}{b^5}\)[/tex] is:
[tex]\[ a^3 b \][/tex]

### Step 5: Match the simplified expression with the options provided
Comparing with the provided options, we find:
- A. [tex]\(\frac{a^3}{b}\)[/tex]
- B. [tex]\(a^3 b\)[/tex]
- C. [tex]\(a^3\)[/tex]
- D. [tex]\(\frac{a^4}{b}\)[/tex]

The simplified expression [tex]\(a^3 b\)[/tex] matches option B.

Thus, the correct answer is:
[tex]\[ \boxed{B} \][/tex]