To find the greatest common factor (GCF) of the expression \(42m - 28n\), we need to look for the GCF of the coefficients of the two terms (42 and 28) and then factor it out.
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Find the GCF of the coefficients:
- The prime factorization of 42 is \(2 \times 3 \times 7\).
- The prime factorization of 28 is \(2^2 \times 7\).
The GCF is the product of the lowest powers of common prime factors:
- For \(2\), the lowest power is \(2^1\).
- For \(7\), the lowest power is \(7^1\).
Therefore, the GCF of 42 and 28 is: \[ 2^1 \times 7^1 = 2 \times 7 = 14. \]
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Factor out the GCF from the expression: \[ 42m - 28n = 14(3m - 2n). \]
Thus, the GCF of \(42m - 28n\) is \(14\), and the expression can be factored as: \[ 14(3m - 2n). \]