MHB Calculating LCD and GCD of 2 Sets of Numbers

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The discussion focuses on calculating the greatest common divisor (GCD) and least common multiple (LCM) of two sets of numbers expressed in their prime factorizations. For the GCD, the common prime factors are identified, leading to the conclusion that the GCD is \(2 \cdot 3^2 \cdot 7\). For the LCM, the process involves finding the highest powers of all prime factors present in both sets, resulting in \(2^3 \cdot 3^3 \cdot 5 \cdot 7 \cdot 11\). Participants clarify that the calculations do not require multiplying out the numbers, as the prime factorization approach is sufficient. The discussion emphasizes understanding the relationships between GCD and LCM through prime factorization.
karush
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Determine
$\textit{gcd}(2^4 \cdot 3^2 \cdot 5 \cdot 7^2,\quad 2 \cdot 3^3 \cdot 7 \cdot 11)$
and
$\textit{lcm}(2^3 \cdot 3^2 \cdot 5,\quad 2 \cdot 3^3 \cdot 7 \cdot 11)$

ok the example appeared to have combine the 2 sets on gcd but I am still ?

there is no book answer for this:confused:
 
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Greatest Common divisor ... think about how you would factor out the common terms from both prime decompositions if they were added

$(2^4 \cdot 3^2 \cdot 5 \cdot 7^2) + (2 \cdot 3^3 \cdot 7 \cdot 11)$

${\color{red}(2 \cdot 3^2 \cdot 7)} \bigg[(2^3 \cdot 5 \cdot 7)+ ( 3 \cdot 11) \bigg]$Least Common Multiple ... think about obtaining a common denominator if both prime factor decompositions were denominators of two fractions

$\dfrac{x}{2^3 \cdot 3^2 \cdot 5} + \dfrac{y}{2 \cdot 3^3 \cdot 7 \cdot 11}$

$\dfrac{x(3 \cdot 7 \cdot 11) + y(2^2 \cdot 5)}{\color{red} 2^3 \cdot 3^3 \cdot 5 \cdot 7 \cdot 11}$
 
well that makes a lot more sense

i don't think there is any need to multiple these out:cool:
 
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