Answer:
(5 + 7i)
Step-by-step explanation:
recall that the complex conjugate root theorem states that for a polynomial with real coefficients and with a complex root a + bi, then the other root must be the complex conjugate a - bi
in our case we are given that the polynomial (which we will assume to have real coefficients) has a complex root (5 - 7i)
if we compare this with our explaination above, we can see that a = 5 and b = -7.
hence the other root must be the complex conjugate of (5 - 7i) which is (5 + 7i)
