# Chapter P, Prerequisites - Section P.7 - Rational Expressions - P.7 Exercises: 1

(a) rational (b) not rational (c) rational

#### Work Step by Step

(a) $\displaystyle \frac{3x}{x^{2}-1}$ is a rational expression because it is a ratio of two polynomials. (b) $\displaystyle \frac{\sqrt{x+1}}{2x+3}$ is not a rational expression because the numerator $\sqrt{x+1}$ is not a polynomial. (c) $\displaystyle \frac{x(x^{2}-1)}{x+3}=\frac{x^{3}-x}{x+3}$ is a rational expression because it simplifies to a ratio of two polynomials.

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