Write the expression as either the sine, cosine, or tangent of a single angle.
cos(π/3)cos(π/5) + sin(π/3)sin(π/5)

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?

Factor the polynomial, if possible. if the polynomial cannot be factored, write prime. 9n^3 + 27n^2 – 25n – 75

Sophia wrote an equation to represent the revenue of a movie theater for one day. she let x represent the number of child tickets sold and y represents the nunver of adult tickets sold. if a child ticket cost $4, an adult ticket cost $6, and the total revenue for the daybwas $420, which equation could sophia use to represent the number of chikd and adult tickets that were sold?