LCD(15, 7, 8) = 840.
The LCD of x, 5, 7, 15 is 105x.
Alright, honey, let me break it down for you. The common denominator for 8 and 15 is 120. Why? Because it's the smallest number that both 8 and 15 can divide into without leaving a remainder. So there you have it, simple math for your beautiful brain to digest.
15
LCD(5, 15) = 15
15
360
120
LCD is 24
15
15
The LCD of 13, 14 and 15 is 2730 The LCD of 1/3, 1/4 and 1/5 is 60