Answer:
b. 80
Step-by-step explanation:
The is 20 characters long
Differentiating both sides of

with respect to <em>x</em> yields (using the chain rule)

Solve for d<em>y</em>/d<em>x</em> :

The answer is then D.
Answer:
o 200
fctvtvtv
Step-by-step explanation:
O200 o200