Sum of first n terms of an ap sequance is 3n2+5n. what is the sum of its first n+1 terms. find the sum of its first 10 terms. ​

a) 3n^2 + 11n + 8

b) 350

Step-by-step explanation:

10) 3(10^2)+ 5*10 = 350

n+1) 3(n+1)^2 + 5(n+1)

        3(n^2 + 2n + 1) + 5n+5

         3n^2 + 6n+3 + 5n + 5

           3n^2 + 11n + 8

i would need to see the dot plot : )