Question

Sn=3n²6n,
find
D
and
10th
term of AP​

Answer 1

Answer:

mark brialint answer plz

Answer 2

Answer:

d=6

a10=63

hope this helps

mark me as brainlist

thank u

Step-by step

Sn = 3n^2 + 6n

=> n/2 [ 2a + (n-1) d] = n (3n + 6)

=> [ 2a + (n-1) d] = 2 (3n +6)

=> 2a + (n-1) d = 6n + 12

=> 2a + (n-1)d = 18 + 6n - 6

=> 2a + (n-1)d = 18 + 6(n-1)

On Comparing both sides, we get

2a = 18

=> a = 9

And, d = 6

a10=a+(n-1)d

    =9+9*6

       =54+9

      =63