the LCD of 2, 9 and 5 = 90
LCD(11, 16) = 176
126
the answer is 45. You compute it by reducing each number to its prime factors, and taking the unique set. 9 factors to 3x3, 15 to 3x5, so the unique set is one 3 from the 9, one 3 that they share and one 5 from the 15. 3x3x5=45. Of course, 135 is also a common denominator but isn't the least. you can always find a CD by multiplying the two. The LCD will make simplification after the addition or subtraction of fractions much easier.
LCD is y E
the LCD of 2, 9 and 5 = 90
99
99
lcd(22, 12, 16, 9) = 1584 22 = 2 x 11 12 = 2^2 x 3 16 = 2^4 9 = 3^2 lcd = 2^4 x 3^2 x 11 = 1584
LCD(4, 2, 9) = 36
LCD(7, 9, 2) = 126.
LCD(8, 11, 9) = 792
LCD(11, 16) = 176
since 9 and 11 have no common factors, the LCD is 99
LCD(11, 9, 6) = 198
22
LCD(9, 3y) = 9y