Answer:
-420
Step-by-step explanation:
Answer:
c
Step-by-step explanation:
Answer:

Option D is correct option.
Step-by-step explanation:
We are given: 
We need to find f(x+h)
For finding f(x+h) we need to replace x by x+h

Finding f(x+h) we get:

Option D is correct option.
I'm not sure what you're asking but they each took 5 hours of work into one hour..