In the given triangle , Coordinates of A (-1,3) , B (-5,-1), C (3,-1).
Let's find the slope of AB and AC .
Formula of slope is

For AB, slope is,

And slope of AC is

Product of the slopes of AB and AC is

Since the product of the two slopes is -1, so AB and AC are perpendicular.
And if they are perpendicular, angle BAC is 90 degree, so the triangle is right triangle .
Now we check the length of the sides of the triangle, and for that we use distance formula , which is

So for AB,

For AC,

For BC,

And since two sides are equal, so the triangle is isosceles triangle .