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Factor the each monomial.
\72a3b2= 2 · 2 · 2 · 3 · 3 · a · a · a · b · b
\86a = 2 · 43 · a
\The GCF is the product of the common prime factors in each monomial.
\GCF = 2 · a
\The greatest common factor of 72a3b2 and 86a is 2a.![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
The greatest common factor of 72a3b2 and 86a is 2a.