The graph of f(x)=x3+5x+1\displaystyle {f{{\left({x}\right)}}}=-{x}^{{3}}+{5}{x}+{1} is shown below.
Estimate the solution(s) to the equation f(x)=8\displaystyle {f{{\left({x}\right)}}}={8}.

1234-1-2-3-41234567891011-1-2-3-4-5-6-7-8-9-10-11

Enter solution(s) in the box below. If there is more than 1 solution, separate the values with a comma (example: -3, 2, 4.5).