Question 1138584
the factors are (x-1)^2(x+3)(x-5)
multiplicity 2 means squared and the other factors give the zeros wished
(x^2-2x+1)(x^2-2x-15)
x^4-2x^3-15x^2-2x^3+4x^2+30x+x^2-2x-15
x^4-4x^3-10x^2+28x-15
{{{graph(300,300,-10,10,-100,100,x^4-4x^3-10x^2+28x-15)}}}