I don't mean to be clicking just to get a point without answering the question but there's no comment option.
Is there more to the question, any more info?
We'll use rise over run to find the slopes of two of the sides of the triangle:

Because C is the rightmost point, we'll have it represent (x1,y1), and have A and B represent (x2,y2):
A to C
(-2,3) to (2,-1)

The slope of the line from A to C is -1.
B to C
(-3,-6) to (2,-1)

The slope of the line from B to C is 1.
These lines intersect at (2,-1), and they have negative reciprocal slopes of each other, which creates a perpendicular angle. This means that triangle ABC is a right triangle, and angle ACB is the right angle.
Answer:
sometimes true
Step-by-step explanation:
Answer:
what is the blank for
Step-by-step explanation:
sorry I mean bank