Borders for a Rectangle

Question

Amanda is adding a border to a rectangular quilt with a length of 4 feet and a width of 3 feet. The border has a width of x feet. Write a quadratic function f (x) in standard form for the area of the border in square feet. What is f (0.5) and what does it represent?

Answer 1

The border is also a rectangle!!!!!!!
It is having a length =4+2x and width 3+2x

Area of the border=(4+2x)(3+2x)-3*4
f(x) =4x^2+14x
if x=0.5 f(0.5)=4*(1/4)+14*(1/2)=8
You can verify that 5*4-4*3=8 sq units