Answer:
(2*n)+9=n-30
Step-by-step explanation:
I'm not sure but I think that is the equation
Answer:
1.38p=C
Step-by-step explanation:
each pound is $1.38 and pounds is p they have to equal to C, the total.
Answer:
The answer is 
Step-by-step explanation:
Assuming the snowball is a perfect sphere, then if A denotes the surface area and D the diameter then:

Differentiating wrt r we have:

We are told that
and we want to find 
By the chain rule we have:

∴
∴
When D=10 then

The sign (-) shows that the D is decreasing.