No one helped me with the last one so can SOMEONE HELP ME NOW

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

An arc subtends a central angle measuring 7pi/4 radians what fraction of the circumference is this arc?

Prove that (x-2)is factor of p (x)=2x³-3x²-17x+30