" Life is not a problem to be solved but a reality to be experienced! "
© Copyright 2013 - 2024 KUDO.TIPS - All rights reserved.
a4=1/2*8=4
a8=4²=16
4r=16-4=12
r=3
a1+3r=a4
a1=4-3*3
a1=-5
Odp. a1=-5, r=3