How do you answer 14x-13=9x+2?

Write a polynomial that fits the description: a third-degree polynomial with leading coefficient -4

You have a square piece of cardboard that measures 14 inches on each side. to build a box, you cut congruent squares out of each corner of the cardboard. use the picture to find the area of the cardboard you were used to build the box

In a column proof the right column states your reasons