Can I get help solving this problem. I already tried the answer for real zeros: -1, 1, 4 and for the factoring (x²-5)(x+1)(x-1)(x+4) but it says it's wrong.

Find all real zeros of the given polynomial function 1'. (Enter your answers as a comma-separated list.) f(x)=x5+4x46x324x2+5x+20 x= ,E, 1,1,4 a: Factor f(x) using only real numbers. (x+1)(x3+4x25x20) ' X m l f(X) =