find distance between (-3,-2) and (7,-6)

The distance formula is:  d  =  √[ (x2 - x1)² + (y2 - y1)² ]

It makes no differnce which point you call (x1, y1) and which point you call (x2, y2).

If  (x1, y1) = (-3, -2)  and  (x2, y2) = (7, -6),

then  x1 = -3    y1 = -2    x2 = 7    and     y2 = -6

Substituting:                d  =  √[ (7 - -3)² + (-6 - -2)² ]

                                   d  =  √[ (10)² + (-4)² ]

                                   d  =  √[ 100 + 16 ]

                                   d  =  √[ 116 ]

                                   Reduce, if you wish.