Word Problem

Question

Congruent squares, with side lengths of x, are cut from the corners of a 10 inch by 14 inch piece of cardboard to form an open box. What equation models the surface area,y, of the open box after the corners are cut away?

I need the steps, along with the answer please!

Answer 1

Two "x" are cut from the length, and two "x are cut from the width. 

 

The bottom of the box now has a length of 14 - 2x, and a width of 10 - 2x. The height of the box is x.

 

The area of the bottom is (14 - 2x)(10 - 2x).

Two faces are x(14 - 2x), or a total of 2x(14 - 2x)

Two faces are x(10 - 2x), or a total of 2x(10 - 2x)

 

The surface area (bottom and four faces) is 

 

(14 - 2x)(10 - 2x) + 2x(14 - 2x) + 2x(10 - 2x)