Please help mee with this thing

Proceed as in example 3 in section 6.1 to rewrite the given expression using a single power series whose general term involves xk. ∞ n(n − 1)cnxn − 2 n = 2 − 4 ∞ ncnxn n = 1 + ∞ cnxn n = 0

The value of the expression 16-^3/4 8 1/8 -6 6 1/40 1/64

Factor and solve to find roots x squared -x - 90 =0