Answer
The result is negative.
Work Step by Step
$a$ is a negative number.
Subtracting $b $ (which is negative) is the same as adding $-b$ (which is positive)
so,
$a-b=a+(-b)$
and we have a positive number $(-b)$ being added to a negative number $(a)$
The number $a$ has greater absolute value (distance from 0),so
the result is negative.