a3=a1+2d
-2=a1+6
a1=-8
22=a1+nd-d
22=-8+3n-3
22+11=3n
n=11
1.a3=a1+2d
-2=a1+2*3
a1=-2-6=-8
2. an=a1+(n-1)d
22=-8+(n+1)3
22+8=3n+3
30-3=3n
27=3n
n=9
a3=a1+2d
-2=a1+6
a1=-8
22=a1+nd-d
22=-8+3n-3
22+11=3n
n=11
1.a3=a1+2d
-2=a1+2*3
-2=a1+6
a1=-2-6=-8
2. an=a1+(n-1)d
22=-8+(n+1)3
22+8=3n+3
30-3=3n
27=3n
n=9