Number of faces: F=a+3
Number of vertices: V=2a
Number of edges: E=4a-1
V+F-E=2
Replacing V=2a; F=a+3; and E=4a-1 in the formula above:
(2a)+(a+3)-(4a-1)=2
Eliminating parentheses:
2a+a+3-4a+1=2
Adding similar terms:
(2+1-4)a+(3+1)=2
(-1)a+4=2
Solving for a. Subtracting 4 both sides of the equation:
(-1)a+4-4=2-4
(-1)a=-2
Dividing both sides by (-1)
(-1)a/(-1)=-2/(-1)
a=2
Answer: The value of a is: a=2
Answer:
399
Step-by-step explanation:
9+4^3*(20-8)/2+6
9+(4)(4)(4)(12)/2+6
9+64(12)/2+6
9+768/2+6
15+768/2
15+384
399
On = 38 - 9n
Step-by-step explanation:
Note the common difference d between
consecutive terms
d= 20 - 29 = 11 - 20 = - 9
This indicates the sequence is arithmetic with n
th term
On
= apt (n - 1)d
where a, is the first term and d the common
difference
Here a, = 29 and d=- 9, thus
An = 29 - 9 (n - 1) = 29 - 9n + 9 = 38 - 9n
Answer:
f(g(x)) = 2x + 7; g(f(x)) = 2x+13; f(g(4)) = 15
