Remember the chain rule.
L(x)=f(g(x))
L'(x)=f'(g(x))g'(x)
take the derivative of f(g(x)). just treat them like they are variables. so you get:
h'=f'(g(x))g'(x)
now plug in your x value and evaluate:
h'(1)=f'(g(1))(g'(1))
substitute in values that you know and evaluate again
h'(1)=f'(3)(-3)
h'(1)=(-5)(-3)=15
We can divide 18 pounds by 2/3 pounds to find how many servings of meals the dogs will have.
We will use the keep change flip rule to solve this.
18 / 2/3 is then the same as 18 x 3/2
We then multiply across to get
54/2
This would be 27 meals that the food will last
This is not a complete question i cannot help.... Sorry about that! If you would like to revise the question i would be happy to help.