Respuesta :

The answer is: 3 (x + 7)

Explanation:

3 can go into 3x one time.
3 can go into 21 seven times.

Therefore when factorized it is written as:

3 (x + 7)

Answer:

3 (x + 7)

Step-by-step explanation:

3 can go into 3x one time.

3 can go into 21 seven times.

Therefore when factorized it is written as:

3 (x + 7)