Answer:
B
Step-by-step explanation:
[tex]\sin{x}=\frac{5}{13}, \cos{x}=\sqrt{1-(\frac{5}{13})^2}=\frac{12}{13}[/tex]
[tex]\sin{y}=\frac{8}{17}, \cos{y}=\sqrt{1-(\frac{8}{17})^2}=\frac{15}{17}[/tex]
[tex]\cos(x+y)=\cos{x}\cos{y}-\sin{x}\sin{y}\\=\frac{12}{13}\times\frac{15}{17}-\frac{5}{13}\times\frac{8}{17}\\=\frac{140}{221}[/tex]
