Half of a number is at least 14

Half of 28 is 14 so i guess because i dont really understand the question

The factor that is common to both the terms of the expression is 5. So it can be taken out as common to factorize the expression.

5x - 15
= 5 (x - 3)

The expression cannot be factored anymore beyond this point. So this is the final factorization of the given expression.

Thus the answer to this question is option B