Answer:
the answer is 6
Step-by-step explanation:
2x + 9 = 21
2x = 21 - 9
2x = 12
x = 6
Answer:
84 different lineups are possible
Step-by-step explanation:
The order in which the songs are chosen is not important. So we use the combinations formula to solve this question.
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.

In this question:
6 musics from a set of 9. So

84 different lineups are possible
Answer:
5280
Step-by-step explanation:
If the polygons are similar, then the top side is equal to one half of the left side.
Since side (x -1) = 8, then x = 9.