To find the greatest common factor (GCF) of the expressions \(12a^2\) and \(20ab\), we can follow these steps:
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Factor the coefficients:
- The coefficients are 12 and 20.
- The prime factorization of 12 is \(2^2 \times 3\).
- The prime factorization of 20 is \(2^2 \times 5\).
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Find the GCF of the coefficients:
- The common factors of 12 and 20 are \(2^2\).
- Therefore, the GCF of the coefficients (12 and 20) is \(4\).
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Consider the variable parts:
- For \(a^2\) and \(ab\), the common variable factor is the lowest power of \(a\): \(a^1 = a\).
- There is no common factor for \(b\) in \(a^2\) because \(b\) does not appear there.
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Combine the GCF of the coefficients and the variables:
- The overall GCF is \(4a\).
So, the greatest common factor of \(12a^2\) and \(20ab\) is \(4a\).