Question

1. 2 + 7 + 12 + 17 + ...... to 19 terms.
2. 9 + 7 + 5 + 3 .....
to 14 terms​

Answer 1

Step-by-step explanation:

1.a=2,d=a2-a1= 7-2=5,n=19 ,an=?

an= a+( n-1) d

an=2+(19-1)5

2+(18)5

2+90= 92

an=92 = answer

Answer 2

Answer:

1. firstly we have to find last term 2+(19-1)5=92. now the sum of 19 terms is (19/2)(2+92)=893
2. here last term is 9+(14-1)*(-2)=-17.and the sum is (14/2)(9-17)=-56