Answer:
Average rate of change = -6
Step-by-step explanation:
The average rate of change over the interval (a,b) is given by;
[ f(b) - f(a)] / (b-a)........................where interval is (a,b)
(a,b) interval =(-3,1)
Where;
f(x)= -12 (x+2)² +5

Hi there!
Okay, so I was a bit confused by your question, but I tried to make it a bit easier and work out.
There was two ways I did this because I didn't want to NOT answer your question!
What about this:
3.2/15 cannot be simplified lower than what it is. Decimal form is 0.2133333 (repeating). I answered this part because I didn't know what 3. was (I at first thought it was part of the numerator. But now that I look at it again it may have been a question number. But just in case, I answered it like this anyway.)
Next!
I solved 2/15, which also cannot be simplified down lower than what it is. It's decimal form is 0.133333 (another repeating decimal.)
And so as you can see I answered two problems for you. If these are incorrect, let me know!
Hope this helps!
First substitute
(3)(4)/4
then simplify.
12/4
then solve
3