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

$-1$
Simplifying Rational Expressions 1. Factor the numerator and the denominator completely. 2. Divide both the numerator and the denominator by any common factors. The quotient of two polynomials that are additive inverses is $-1$. --- Observe that $4-5x=-(5x-4)$ ... the numerator and denominator are additive inverses .... The expression simplifies to $-1$ $\displaystyle \frac{(5x-4)}{-(5x-4)}$ = $-1$