The answer is: 100/(6+y)
you can ignore these words, its that 20 character thing
You have the following function:

Derivate implictly the previous expression, as follow:

Where you have used that:

Then, the implicit derivative of the given expression is:

Next, solve for y' as follow:

Question 5:
x/3=6
x=3(6)
x=18
Question 4:
2.3k=4.83
k=4.83/2.3
k=2.1
Question 6:
y=3/4-1/2
y=1/4
Question 2:
8r=24
r=3
Hope this helps!! :)