Because 4 people likes both, we take out 4 from the sum of both the number to avoid double count.
People who like both sports = 12 + 16 - 4 = 24
People who do not like either sport = 30 - 24 = 6
You know x, so just plug it in for the answers. Like AB = x + 7, so since x is 3, then AB is 3 + 7 = 10
BD is 2x + 3x -1 = 6 + 9 - 1 = 14
CE is 3x - 1+ 2x + 3 = 9-1+6+3= 17
Infinitely many because if you take the top equation and multiply it by 2 you get the same equation. That means that any number you plug in for x is a solution
