Question 7The fraction $$ \frac{\sqrt{a^2+x^2}-\dfrac{x^2-a^2}{\sqrt{a^2+x^2}}}{a^2+x^2} $$ reduces to:$0$$\dfrac{2a^2}{a^2+x^2}$$\dfrac{2x^2}{(a^2+x^2)^{\frac{3}{2}}}$$\dfrac{2a^2}{(a^2+x^2)^{\frac{3}{2}}}$$\dfrac{2x^2}{a^2+x^2}$