Answer
$(-135 + 360k)^{\circ}$
Where 'k' is any integer(positive or negative).
Work Step by Step
There exist an infinite number of angles that may be coterminal with any given angle. We can find a coterminal angle by adding or subtracting $360^{\circ}$ any number of times to that angle.
For any integer value of k (positive or negative),
$(-135 + 360k)^{\circ}$ will be coterminal with the given angle $-135^{\circ}$.
