Answer:
Step-by-step explanation:
an=4=a1+(n-1)*d=0.25+(n-1)*d
so (n-1)*d=4-0.25=3.75
Sn=a1*n+(n-1)*d
a1*n+3.75=8.5
0.25*n+3.75=8.5
-3.75 -3.75
0.25*n=8.5-3.75=4.75
n=4.75:0.25
n=19
so a19=a1+(19-1)*d=4
0.25+18*d=4
-0.25 -0.25
18*d=3.75
d=3.75/18
d=0.208
so a2=a1+0.208=0.25+0.208=0.458
a2=0.458
