формулы
1)аn=a1+(n-1)*d=5+(14-1)*3=44
Sn=5+44*14/2=343
2)an=12+(24-1)*7=173
Sn=12+173*24/2=2220
3)аn=(-55)+(32-1)*8=193
Sn=-55+193*32/2=2208
4)an=(-7.3)+(19-1)*8=136.7
Sn=-7.3+136.7*19/2=1229.3
5)an=(-16.8)+(26-1)*(-1.2)=-46.8
Sn=-16.8+(46.8)*26/2=-826.8
6)12.56+(104-1)*(-6.4)=-646.64
Sn=12.56+(-646.64)*104/2=-32972.16
формулы
1)аn=a1+(n-1)*d=5+(14-1)*3=44
Sn=5+44*14/2=343
2)an=12+(24-1)*7=173
Sn=12+173*24/2=2220
3)аn=(-55)+(32-1)*8=193
Sn=-55+193*32/2=2208
4)an=(-7.3)+(19-1)*8=136.7
Sn=-7.3+136.7*19/2=1229.3
5)an=(-16.8)+(26-1)*(-1.2)=-46.8
Sn=-16.8+(46.8)*26/2=-826.8
6)12.56+(104-1)*(-6.4)=-646.64
Sn=12.56+(-646.64)*104/2=-32972.16