Question 655920
Find the GCF of the expression. Then factor the expression. 
14y^2+7y-21
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GCF means a factor that is common to 2 or more expressions.
You show only one expression, a trinomial.
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You can say find the GCF of 14y^2, 7y & -21, but not the GCF of a single expression.
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It can be factored:
{{{14y^2 + 7y - 21 = 7*(2y + 3)*(y - 1)}}}
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7 is not a GCF, it's a factor of the trinomial.