This is equal to -3-5/7, or (-3*7)/7-5/7, or -21/7-5/7, or -26/7.
Cos9x - cos5x = -2sin2x.sin7x
sin17x - sin3x = 2sin7x.cos10x
so f(x) =

=
Answer:
-5
Explanation:
Because it’s right
(D): 18-2
Aside from its actual definition—“difference” in math terms talks about and/or means to subtract. The difference is the result/answer to a subtraction problem.
8 (3)-10
24-10=14
Hope this helped :)