I’m not sure if your answer is right but here’s how to solve it
B+c+(c-b)+(b-c). That is your expression. b 11 c 16
First, let's convert the variables to real numbers: 11+16+(16-11)+(11-16)
Now, let's solve that equation. 11+16+5+(-5)
5+(-5) cancels out, so all we have left is: 27
That is your perimeter.
Your model would equal 50,(20+20)=40 +(5+5)=10 .....40+10=50