Three solutions of an nnth order three-point focal type boundary value problem

We consider the following differential equation u(n)(t)=F(t,u(t)),t∈[0,1], together with the three-point focal type boundary conditions u(j)(0)=0,0≤j≤n−3,u(n−2)(p)=0,u(n−1)(1)=0, where 12