: 136.330 Intro to Algebra: GCD
   By Anonymous on Wednesday, October 30, 2002 - 01:28 am: Edit Post

I'm not sure on how to find the GCD (other that trial and error) when you are given three numbers.
12.3:find the greatest common divisor adn the least common multiple of the given set of integers

   By Sasho on Wednesday, October 30, 2002 - 02:01 am: Edit Post

Approach 1: First find the GCD of the first two using the Euclidean Algorithm; call it a; and then find the GCD of a and the third number using the same algorithm. Here is the whole story with the numbers you give. (Note that you may ignore "-" since (-a,b) is the same as (a,b)).


So (90,60)=30.

Next, find (36,30):


So (36,30)=6. Consequently the GCD of 36, 60 and 90 is 6. So, the same is true for the GCD of 36, -60 and 90

Approach 2. Use the fundamental thereom of arithmetic. Roughly, factor all three numbers as product of primes and use the primes "common" to all three.

Posting is currently disabled in this topic. Contact your discussion moderator for more information.