factor completely 3x2 − 21.
3(x2 − 7)
3(x + 7)(x − 7)
3(x + 7)(x − 3)
prime

The fully factored form is 3(x^2 - 7))

Step-by-step explanation:

The only thing you can do with this equation is take out a factor of 3. You cannot simplify the resulting parenthesis without using irrational numbers.

 The correct option is (A)

Step-by-step explanation:  We are given to factorize the following quadratic expression completely :

To factorize the given expression, first we should take common terms out and then we will continue the process.

The factorization is as follows :

Thus, the required factorized form is

Option (A) is correct.

what is the question? i am guessing you are looking for the area.

to find an area, you have to do length x width.

in this case, it would be 12 ft x 4 ft = 48 sq. ft