The length of the rectangle is defined by
.
Geometrically speaking, the rectangle area is equal to the product of its base and its length. According to the statement the area is represented by a <em>third</em> <em>order</em> polynomial and width by a <em>first order</em> polynomial and, thus, length must be a <em>second order</em> polynomial.
By factor the polynomial we get the following roots:

Then, the length of the rectangle is defined by
.
To learn more on rectangles, we kindly invite to check this verified question: brainly.com/question/10046743