Answer:
Step-by-step explanation:
The initial expression is:

Using BEMDAS (Brackets - Exponents - Multiplication - Division - Addition -Subtraction), we first start with brackets:

Remember that if there is a negative sign, it will change the signs of the terms within the brackets.
Then, collecting like terms:

if im mistaken your answer is a. it makes the most sense to me
I think that the answer is -10.6 because its decreasing at a faster rate. What I done to get this answer is to divide 320/3 and we know that it will be a negitive since it clearly says decreasing. Hope this helps
Answer: One of the ways you can do all this is by zearn or by listening by your teacher.