Question

if the sum of first terms of an ap is 3 k- K and its common difference is 6. what is the first term ​

Answer 1

Answer:

(1/2)(3k^3-k^2-6k+6)

Step-by-step explanation:

given sum(s) of first term of a.p is 3k^2-k and it's common difference(d) is 6 and k terms(n)

we know s=(1/n)(2a+(n-1)d)

3k^2-k=(1/k)(2a+(k-1)6)

k(3k^2-k)=2a+6k-6

3k^3-k^2=2a+6k-6

(3k^3-k^2-6k+6)(1/2)=a