$\displaystyle \cos \left (\arcsin \left (\frac{3} {5} \right) + \arccos \left (\frac{4} {5} \right) \right)$ 의 값은?

• ①$\displaystyle \frac{6} {25}$
• ②$\displaystyle \frac{7} {25}$
• ③$\displaystyle \frac{8} {25}$
• ④$\displaystyle \frac{9} {25}$