Geometry the length of a rectangle is repfesented by 4a + 3b, and its width is represented by 3a 2b. write a polynomial for the perimeter of the rectangle. what is the minimum perimeter of the rectangle if a whole number? 12 and b is a non-zero

the correct question is
The length of a rectangle is represented by 4a + 3b, and its width is represented by 3a-2b. Write a polynomial for the perimeter of the rectangle. What is the minimum perimeter of the rectangle if a=12 and b is a non-zero whole number?

we know that
Perimeter of a rectangle=2*[length + width]
length=(4a+3b)
width=3a-2b
so
P=2*[(4a+3b)+(3a-2b)]> P=2*[7a+b]> P=14a+2b

the answer part a) is
A polynomial for the perimeter of the rectangle is P=14a+2b

Part b) 
for a=12
P=14*12+2b> P=168+2b
the minimum perimeter of the rectangle is for b=1
so
P=168+2*1> P=170 units

the answer part b) is 
the minimum perimeter of the rectangle is 170 units