Which of the following expressions is a common factor when the expressions x2 – 16 and x2 +7x + 12 are factored?

A.
x + 3

B.
x - 3

C.
x + 4

D.
x - 4

1 Use this rule: a-b=-(b-a)a−b=−(b−a).

-(16-2)

−(16−2)

2 Use the algorithm method.

16

- 2

14

3 After simplification, we have:

-(16-2)=-14

−(16−2)=−14

4 Therefore, 2-16=-142−16=−14.

-14

−14

for the second one

1 Collect like terms.

7x+(2+12)

7x+(2+12)

2 Simplify.

7x+14

7x+14

step-by-step :

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step-by-step explanatio89