4. Area is found by length times width
area is (12m + 18) and width is 6
its (12m + 18) = 6 ( 2m + 3 )
5. 21x + 51xy and 7(3x + 8xy). She is incorrect. GCF means the greatest common factor so to be correct the factors inside cannot have something in common. Since they have x in common its incorrect. the correct factor by GCF would be 7x(3 + 8y) because all common factors are factored out.
