Given:
The rule of input and output function is:

To find:
The answer if we put 19.
Solution:
Consider the input and output function is:

Substitute
, we get


Therefore, the required answer is 6.
Answer:
The dimensions are:
by 
Step-by-step explanation:
The area of the rectangle is given as

The factored form of this quadratic trinomial gives the dimensions of the rectangle.
We factor 3 first to obtain;

We split the middle term to get;

We factor within the parenthesis to get;

We factor further to get;

The dimensions are:
by 
Then the perimeter will be

Answer:
I believe it would be 21 units . dont let extra line's confuse you just pay attention to the letters its asking for