Given that a polynomial function P(x) has rational coefficients.
Two roots are already given which are i and 7+8i,
Now we have to find two additional roots of P(x)=0
Given roots i and 7+8i are complex roots and we know that complex roots always occur in conjugate pairs so that means conjugate of given roots will also be the roots.
conjugate of a+bi is given by a-bi
So using that logic, conjugate of i is i
also conjugate of 7+8i is 7-8i
Hence final answer for the remaining roots are (-i) and (7-8i).
