The first step to simplifying this expression is to multiply each te in the parenthesis by 3x.
3x × 4

- 3x × 5x
Now calculate the first product in this expression.
12

- 3x × 5x
Calculate the second product in this expression.
12

- 15

Since you cannot simplify this expression any further,, the correct answer to your question is 12

- 15

.
Let me know if you have any further questions
:)