What is 2×(-)=? cause i need the answer for something rlly bad

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

Select a graph that have an equation with a < 0

Average acceleration: i have no idea how to do this.