<span>possible answers:
2x-9y=-37
-5x-6y=10
-2x+9y=-37
5x-6y=10 </span>
Answer:
-1x or 1x
Step-by-step explanation:
Answer:
11.1
Step-by-step explanation:
G o o g l e
The main identity you need is the double angle one for cosine:

We get

Expand the numerator to apply the identity again:




Finally, make use of the product identity for cosine:

so that ultimately,

