Question

the first term of an A. P. is 5 and the common difference is 4. complete the following activity and find the sum of the first 12 terms of the A. P.

Answer 1

Answer:324

Step-by-step explanation:

Formula of Sum of a.p is :-

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

S12=12/2(2×5+(12-1)4]

We have just substituted the given values in the formula

S12=6 [10+11×4]

S12=6 (10+44)

S12=6 (54)

S12=324

Hope it has helped in clearing your doubt !!

Answer 2

Answer:

Step-by-step explanation:

Step-by-step explanation:

Formula of Sum of a.p is :-

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

S12=12/2(2×5+(12-1)4]

We have just substituted the given values in the formula

S12=6 [10+11×4]

S12=6 (10+44)

S12=6 (54)

S12=324