Hello from MrBillDoesMath!
Answer:
25 + 300/x + 900/x^2
Discussion:
( (5x + 30)/x ) ^ 2 =
(5x + 30)^2 / x^2 =
(25x^2 + 2*5*30x + 30^2) / x^2 =
(25x^2 + 300x + 900) / x^2 =
25 + 300x/x^2 + 900/x^2 =
Thank you,
MrB