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What is the Greatest Common Divisor (GCD) of 23 * 32 * 54 and 22 * 34 * 52?
22├Ч32├Ч52
23├Ч34├Ч54
22├Ч32├Ч54
23├Ч32├Ч52
22├Ч32├Ч52
Given: Two numbers are given as prime factorizations: N1тАЛ=23├Ч32├Ч54 and N2тАЛ=22├Ч34├Ч52.
Two numbers are given as prime factorizations: N1тАЛ=23├Ч32├Ч54 and N2тАЛ=22├Ч34├Ч52.
GCD(axтЛЕbyтЛЕcz,apтЛЕbqтЛЕcr)=amin(x,p)тЛЕbmin(y,q)тЛЕcmin(z,r)
To find the GCD of numbers in prime factored form, simply select the smallest exponent for each common prime base present in the factors.
Students often confuse GCD with LCM and mistakenly pick the maximum exponents instead of the minimum exponents.
Identify prime bases and exponents
The prime bases present in both numbers are 2, 3, and 5. We list their exponents for N1тАЛ and N2тАЛ.
N1тАЛ:23,32,54;N2тАЛ:22,34,52
Find the minimum exponent for each base
Comparing exponents: for base 2, min(3,2)=2. For base 3, min(2,4)=2. For base 5, min(4,2)=2.
min(3,2)=2,min(2,4)=2,min(4,2)=2
Calculate GCD
Combine the bases with their respective minimum exponents to get the GCD.
GCD=22├Ч32├Ч52
A is correct because the GCD is obtained by taking the product of the lowest powers of each common prime factor, which results in 22├Ч32├Ч52.
This method is directly applicable to finding the HCF/GCD of algebraic expressions containing variables, e.g., finding the GCD of x2y3 and x3y2.