Question

if the sum of 'n' terms of an ap is given by Sn = 3n square+4n then find its first term​

Answer 1

a +(n-1)d is the formula

Answer 2

here is ur answer:

$s_{n} = 3 {n }^{2} + 4n \\ \\ s_{1} = 3 \times {1 }^{2} + 4 \times 1\\ \\ s_{1} = 3 + 4\\ \\ s_{n} = 7\\ \\ s_{n} = a_{1} \\ \\ a_{1} = 7$

hope it helps you!