Answer:
I think it's 7- 2i over 3. hopefully that helps
((36/9)*7)+36=64
<span>36 volunteers making meals divided by the ratio of volunteers that are making meals (9) multiplied by the ratio of people not making meals (7) plus the 36 people making meals to get the total amount of people (64).</span>
In order to be differentiable everywhere, 
must first be continuous everywhere, which means the limits from either side as 
must be the same and equal to 
. By definition, 
, and
so we need to have 
.
For to be differentiable at 
, the derivative needs to be continuous at , i.e.
We then need to have
Then
