Respuesta :

A square has 4 equal sides.  If the perimeter of this square is 6x-20 units, then the side length is 1/4 of that:
                        6x-20       6x     20
side length = ----------- =  ---- - -----  =  3x/2 - 5
                          4            4       4

Unfortunately, there's not enough info given here to calculate x.  Again, please share the illustration of this square.  Probably the needed info is there.