To rationalize the denominator of the expression $\frac{7}{\sqrt{7}-\sqrt{3}}$, we can use the conjugate of the denominator. The conjugate of $\sqrt{7}-\sqrt{3}$ is $\sqrt{7}+\sqrt{3}$.
We multiply the numerator and denominator by the conjugate:
$$\frac{7}{\sqrt{7}-\sqrt{3}} \times \frac{\sqrt{7}+\sqrt{3}}{\sqrt{7}+\sqrt{3}}$$
Expanding the numerator and denominator:
$$\frac{7(\sqrt{7}+\sqrt{3})}{(\sqrt{7}-\sqrt{3})(\sqrt{7}+\sqrt{3})}$$
Simplifying the denominator:
$$\frac{7(\sqrt{7}+\sqrt{3})}{(\sqrt{7})^2 - (\sqrt{3})^2}$$
This simplifies further:
$$\frac{7(\sqrt{7}+\sqrt{3})}{7-3}$$
And finally, we simplify the expression:
$$\frac{7(\sqrt{7}+\sqrt{3})}{4}$$
So, the rationalized form of $\frac{7}{\sqrt{7}-\sqrt{3}}$ is $\frac{7(\sqrt{7}+\sqrt{3})}{4}$.
