Question

a=2,d=8,Sn = 90, find n and an​

Answer 1

Answer:

hope it help you!

Step-by-step explanation:

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

90=n/2[2+(n-1)8]

90x2=n(2+8n-8)

180=n(8n-6)

180=8n^2-6n

8n^2-6n-180=0