Answer
False.
Irrational numbers can be positive or negative.
Example: $-\sqrt3$, $-\frac{\pi}{4}$
Work Step by Step
Irrational numbers is the set of all numbers whose decimal representations are neither terminating nor repeating and they cannot be expressed as a quotient of integers. But they can be positive or negative.
Example:
-1.73205..... $\approx$ $-\sqrt3$, 1.73205.... $\approx$ $\sqrt3$
-2.2360679.... $\approx$ $-\sqrt5$
$-\frac{\pi}{4}$, $\frac{\pi}{4}$
