# Math Help - LCD of fractions

1. ## LCD of fractions

Find the LCD of the following fraction.

3/a , 3/b , 1/5

2. Originally Posted by cutiepi_86
Find the LCD of the following fraction.

3/a , 3/b , 1/5

How would you find the LCM of 3, 5, and 7? It's simply 3*5*7 = 105.

In this case we need the LCM of a, b, and 5. Since we can't factor any of a, b, or 5 the best we can do is multiply them:
a*b*5 = 5ab.

So the LCD of 3/a, 3/b, and 1/5 is 5ab.

-Dan