The band knows 45. song. it play 12 songs in the first set, 15 song in the second set, and 11 songs in the last set. if no songs were repeated, how many songs does the band know that it didn't play

7 songs

Step-by-step explanation:

12+15+11 is 38

45-38 is 7.

your answer would be 10x - 1

18

step-by-step explanation:

draw the shape and you will see that f and k are actually at adjacent vertices (points of the hexagon that are neighboring).   so find the distance between (1,2) and (4,2).   that is easy since (1,2) and (4,2) is just a vertical distance to count, which is 3.   it is a regular polygon which means all sides are congruent.   you have 6 sides (hexa) so multiply 6 by 3 to receive 18.