Respuesta :

Answer:

a 2-a1=18-9=9

a3-a2=27-18=9

a4-a3=36-27=9

a5-a4=45-36=9

a6-a5-54-45-9

a7-a6=63-5459

a8-a7=72-63=9

a9-a8=81-72=9

a10-a9-90-81-9

The difference between every two adjacent members ofthe series is constant and equal to 9