If a polyhedron has 15 edges and 9 vertices how many face will it have?
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8

Step-by-step explanation:

E = 15, V = 9, F =?

By Euler's rule, we have:

F + V - E = 2

F + 9 - 15 = 2

F - 6 = 2

F = 6 + 2

F = 8

arithmetic sequence

step-by-step explanation:

given that a sequence has terms as

19, 15, 11,

this is represented on a graph

the pattern indicates that the sequence is an arithmetic sequence with i term

a=19 and common difference d =-4

any general term

thus the sequence is reduced by 4 for each successive term starting from 1 and nth term is

24-5n.

first negative term would start after 5th term

5th term =24-25< 0

from 5th term onwards the sequence would be negative.