Let f be a function such that

f(-1)=3 and f'(-1)=6

let h(x)=x^5f(x)
evaluate h'(x) at x=-1

h'(x)=5*x^4*f(x)+x^5*f'(x)

h'(-1)=5*(-1)^4*f(-1)+(-1)^5*f'(-1)=
5*1*3+(-1)*6=15-6=9