Isolate the identity

cos 2x - cos 8x
cos 2x + cos 8x

HELP PLS

Ling listed all of the factors of a mystery number: 1,2,4,8,16,32 what is the mystery number?

In the following diagram it is given that dec, ab || dc, ad || eb, and ad is congruent to bc. a)why isn't abc a parallelogram even though it has a pair of parallel sides and a pair of congruent sides b)explain why be must be congruent to bc. further explain what type of triangle this makes triangle abc and what it tells you about angle 1 and angle 2c) finally why must angle 3 be congruent to angle 1? further, explain why we know that angle 3 is congruent to angle 2

15 there is a line that includes the point 0,10 and has a slope of 7/4. what is it’s equation in slope intercept form