Question

if the first term of an ap is -5 and the common difference is 2 find the sum of first six terms.

ch 5 arithmetic progression
class 10

please answer fast​

Answer 1

Answer:

Step-by-step explanation:

Sn=n/2+[2a+(n-1)d]

n=6

a=-5

d=2

S6=6/2+[2*-5+5*2]

    =3+[-10+10]

    =3

Answer 2

Answer:

63 is the sum of the first 6 numbers

Step-by-step explanation:

The formulae for finding the sum of the terms of ap is n/2 [a+l]

here n means number of terms , a means first term , l means last term d means difference

n=6

a=-5

l=26

6/2[-5+26 ]

3[21]

63