Question 515185: Find the LCM of (9+7r), (81-49r^2), and (9-7r)
Thanks,
Dee
Answer by drcole(72)   (Show Source):
You can put this solution on YOUR website! To find the least common multiple, we need to first factor each of the expressions. The first,  , and the third,  , cannot be factored, but the second,  , is the difference of two squares:
 and 
Remembering that every difference of two squares  can be factored as:
we get that
So we are trying to find the least common multiple of ,  , and . The least common multiple of three expressions A, B, and C is the simplest expression that contains A, B, and C in its factorization. So the least common multiple has to contain at least one and one in its factorization, since those appear in A and C. Do we need anything else? No, because , so doesn't add any new factors to the least common multiple. So the least common multiple must be or .
|
|
|
