The correct answer is the Last Choice ft equals truth
For this case we have the following expression:

By definition, a coefficient is the term that accompanies one or more variables.
For example:

The coefficient of the linear term is 3.
So, in the given expression we have to:
-4 is the term that accompanies the variables xy.
Answer:
-4
Multiply 9 by 2a and 2, and you get 18a + 18. Another equivalent expression would be 18(a+1), which you can get by factoring the above answer.
Slope is undefined as the answer is 6/0