Question

what is he lenght of segment qith endpoints(2,-3) and (-2,-6)

Answer 1

The formula for the distance between two points is\[d = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\] It doesn't matter which point you call (x1, y1) and which point you call (x2, y2). If you draw yourself a little picture, you'll see that this is just using the Pythagorean theorem to find the hypotenuse of a triangle where the hypotenuse is the segment between the two points.