Answer: 
Step-by-step explanation:
Given

We can write it as

Express x in terms of y

Replace y be x to get the inverse

To prove, it is inverse of f(x). 

So, they are inverse of each other.
Answer:
cat food a
Step-by-step explanation:
6.5/10 = 0.65 unit price
14/20 = 0.70 unit price
5/11 = 18/y
5 y = 18 · 11
5 y = 198
y = 198 : 5
y = 39.6
AB = sqrt(10^2 - 4^2) = sqrt(100 - 16) = sqrt(84) = sqrt(4 x 21) = 2sqrt(21) = 2 radical 21.