Respostas

2014-07-21T19:10:18-03:00
An= a1 + (n-1). r
a7= a1 + (7-1). r
-49= -73 + 6. r
-49 + 73= 6. r
24= 6. r
r= 24/6
r=4
2014-07-21T19:17:10-03:00

a7= a1+ 6r

-49= -73 + 6r

-6r= -73 +49

-6r= -24

r= 24/6

r= 4