The question asks how to rationalize the denominator of the given expression $\frac{\sqrt{5}}{\sqrt{7}}$. To rationalize the denominator, we need to eliminate the square root from the denominator by multiplying both the numerator and the denominator by the same square root present in the denominator.

The correct step is:

• Multiply both numerator and denominator by $\sqrt{7}$. This makes the denominator $(\sqrt{7} \cdot \sqrt{7}) = 7$, which is rationalized.

So, the correct answer is (a) multiply by $\sqrt{7}$.

Would you like a detailed explanation of why rationalizing works? Let me know!

Related Questions:

1. How do you rationalize the denominator for expressions like $\frac{1}{\sqrt{a} + \sqrt{b}}$?
2. Why is it important to rationalize the denominator in mathematical expressions?
3. How do you simplify $\frac{\sqrt{6}}{\sqrt{2}}$?
4. What happens if you multiply by the conjugate of the denominator instead?
5. How can rationalizing be applied to higher-degree roots, like cube roots?

Tip:

When rationalizing, always focus on making the denominator a whole number by multiplying by the appropriate root or its conjugate.