Step 1 : find the slope using the equation using the pair of coordinates that are given i.e A (−7,14) B (−21,28) ( name them A and B respectively so they can be easily named as x1, y1 and x2,y2 respectively)
m = y2-y1/x2-x1
m = 28-14 / -21 -( -7)
m = 14 / -14
m = -1
Step 2 : Find the y intercept using the line of equation (use and one of the given coordinates either A or B)
Every time you play a song 8 different songs can be played, since you do this 3 times: Or, an easier way to write this if play them many times: In which the 8 is how many options and the 3 how many times you play.