So here we just are gonna distribute and simplify.
Answer: 8 vertices
Step-by-step explanation: A cube has 6 square faces. Each segment formed by the intersection of 2 faces is called an edge so a cube has 12 edges. Each point formed by the intersection of 3 edges is called a vertex so a cube has 8 vertices.
Answer:
8
Step-by-step explanation:
15 x (1/3+1/5) make common denominators and add
15 x (5/15+3/15) add fractions
15/1 x (8/15) 15 and 15 cancel out and become 1
1/1 x 8/1
1 x 8
8
X = 18°
cos 54° = sin 36°
cos 3 x = sin 2 x
cos ( 2 x + x ) = sin 2 x
cos 2 x cos x - sin 2 x sin x = 2 sin x cos x
( cos² x - sin² x ) cos x - 2 sin² x cos x = 2 sin x cos x / : cos x
( divide both sides by cos x )
cos² x - sin² x - 2 sin² x = 2 sin x
1 - sin² x - 3 sin² x - 2 sin x = 0
- 4 sin² x - 2 sin x + 1 = 0 substitution: u = sin x
- 4 u² - 2 u + 1 = 0
u = 2 -√20 / - 4
sin 18° = (√ 5 - 1 )/4 
cos 18° = √( 1² - ((√5 - 1)/4)²
cos 18° = (10+2√5)^(1/2) / 4