son 30 y si sumas con 20 son 96
Answer:

Step-by-step explanation:
First, notice that:



We proceed to use the chain rule to find
using the fact that
to find their derivatives:

Because we know
then:
We substitute in what we had:

Now we put in the values
in the formula:

Because of what we supposed:

And we operate to discover that:


and this will be our answer
Because if let's say you have 400$ for the year, and each book cost 10$. So it would be written as 400-10b since the quantity of books must be multiplied times their cost to calculate whether you are within or outside the budget.
Answer:
the slope is equal to one half ot 1/2