$h(x)=f(x)+g(x)-18$ is polynomial with degree $\leq 2$ and has roots $a,b,c$ so $h(x) \equiv 0$ and $g(x)=18-f(x)$ $g(d)=18-f(d)=8$

RagvaloD wrote: has roots $2,3,7$ I think roots are $a,b,c$

targo___ wrote: RagvaloD wrote: has roots $2,3,7$ I think roots are $a,b,c$ Yes.Correct. $a,b,c $ are the roots