[gohrt]

    f(x) = x^2 + 11x  

OR f(x) = x

    f(10) = 110

     = 1 * 10^2 +  1 * 10^1
     = 0 * 10^2 + 11 * 10^1

    f(0) = 0
     = 1 * 0^2 +  1 * 0^1
     = 1 * 0^2 + 11 * 0^1