## College Algebra (6th Edition)

domain: $\mathbb{R}$ interval notation: $(-\infty,\infty)$
See example 1. Division by 0 is undefined, so $f(x)$ will be defined for all real numbers except for the number(s) x that yield zero in the denominator: $x^{2}+49=0$ $x^{2}=-49$ ... no real number has a negative square... ... so, the denominator is never zero, $f$ is defined for all real numbers domain: $\mathbb{R}$ interval notation: $(-\infty,\infty)$