Answer:
x^3-10x^2+x+120
Step-by-step explanation:
Assuming you mean roots -3, 5, 8
These happen when we have (x+3)(x-5)(x-8)=0
Expand this
(x^2-2x-15)(x-8)=0
=x^3-2x^2-15x-8x^2+16x+120
=x^3-10x^2+x+120
