Answer:
119/169
Explanation:
We use the following trig identity
[tex]\cos2x=1-2\sin^2(x)[/tex]
Now in our case, we know that
[tex]\sin x=-\frac{5}{13}[/tex]
therefore, our formula gives
[tex]\cos2x=1-2*(\frac{5}{13})^2[/tex]
which simplifies to give
[tex]\boxed{\cos2x=\frac{119}{169}.}[/tex]
