$\frac{\sqrt{40\cdot9}}{\sqrt{49}}$
\(\frac{\sqrt{40\cdot9}}{\sqrt{49}}=\sqrt{\frac{2^3\cdot3^2\cdot 5}{7^2}} =\frac{2\cdot 3}{7}\cdot \sqrt{2\cdot 5}=\color{blue}\frac{6}{7}\sqrt{10}\)
!
!
