Question

Congruent squares, with side lengths of x, are cut from the corners of a 12-inch-by-16-inch piece of cardboard to form an open box. Which equation models the surface area, y, of the open box after the corners arw cut away ?

Answer 1

The equation would be 192 - 4x^2.

Without the corners missing, the area of the box would be 12 x 16 = 192.

However, we have to subtract each of the missing corners. The have a length and width of x, so their area is x^2. We need to subtract all 4 from 192.