M= 4
Hope that helps have a great day!
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

In standard form it would be y= 5x - 4