## Introductory Algebra for College Students (7th Edition)

Length = $x^{3}-2$
Factoring the expression for the area, $7x^{4}-14x=7x\cdot x^{3}-7x\cdot 2$ $=7x\cdot(x^{3}-2)$ Since the area of a rectangle equals (length)$\times$(width), and one factor of the area is $7x$, the width, it follows that the other factor must be the length. Length = $x^{3}-2$.