Question

Tawanna is asked to find the GCF of each term in the expression 2 a b + 8 b. Her work is shown below.

Factors of 2ab: 1, 2, a, and b
Factors of 8b: 1, 2, 4, 8, and b
GCF: (1) (1) (2) (2) (b) (b)

Which best describes the error in Tawanna’s solution?
Tawanna factored one or both pieces of the expression incorrectly.
Tawanna did not include each factor in the GCF.
Tawanna should have used each common factor once.
Tawanna included only one of the variables in her solution.
Mark this and return

Answer 1

Tawanna should have used each common factor once.

Explanation:

Tawanna is asked to find the GCF of each term in the expression 2 a b + 8 b.

Factors of 2ab: 1, 2, a, and b

Factors of 8b: 1, 2, 4, 8, and b

GCF: (1) (1) (2) (2) (b) (b)

GCF = Greatest common factor

She has calculated the GCF incorrectly as she should use each common factor once only. But she has taken all the common factors twice which is wrong.

Hence, the error in Tawanna’s solution is that "Tawanna should have used each common factor once.". Hence, the correct option is (c).