Posted by thresea on .
what are rational expressions? Why must we always be mindful of the final value of the denominator in a rational expression? For example, consider the rational expression 3x/(x2 – 16). What values in the denominator must we be mindful of? Explain why.

algebra 
Steve,
a rational expression is a fraction where the numerator and denominator are polynomials, such as the example above.
The reason for being careful about the denominator is that if it is zero, the fraction is undefined.