Question 7When simplified, the third term in the expansion of $$ \left(\frac{a}{\sqrt{x}}-\frac{\sqrt{x}}{a^2}\right)^6 $$ is:$\dfrac{15}{x}$$-\dfrac{15}{x}$$-\dfrac{6x^2}{a^9}$$\dfrac{20}{a^3}$$-\dfrac{20}{a^3}$