y,z,16,35,x,91 Assume the general term is quadratic:<--general term Substituting n=3, T3=16 Substituting n=4, T2=35 Substituting n=6, T6=91 We have the system of equations: Solve that system of equation and get A=3, B=-2, C=-5 Substitute into our assumed general term: . Substituting n=5 . Substituting n=1 . Substituting n=1 The sequence is -4,3,16,35,60,91,128,171,220,275,336,403,... Edwin