Find x3+y3 if x+y=5 and x+y+x2y+xy2=24.
Compute the following: (2001×2021+100)(1991×2031+400)20114.
Prove the following formulae are true: an+1−bn+1=(a−b)(an+an−1b+⋯+bn);a2n+1+b2n+1=(a+b)(a2n−a2n−1b+a2n−2b2−⋯+b2n).