## Calculus with Applications (10th Edition)

$x>3$
The "(3..." indicates that numbers in this interval are greater than 3 (but never equal to 3, since the left endpoint is not included in the interval). The "...$\infty$)" indicates that these (positive) numbers can be unbounded in magnitude so there is no right endpoint. In brief, this interval contains all numbers greater than 3. For a number x from this interval, we can write $x>3$