8/x + 2/1 + 8/2 = 5/1
When we have a whole number like 5, the bottom of the fraction is 1, as in 5/1. Since everything has a factor of 1, the 1 doesn't really do anything, so we can ignore it for the purpose of finding LCDs.
The bottoms of our fractions are x and 2. Since x and 2 have no common factors, the LCD is just x * 2
Answer: The LCD is 2x.