If –3 + i is a root of the polynomial function f(x), which of the following must also be a root of f(x)?

a)-3-i
b)-3i
c)3-i
d)3i

we know that

The conjugate root theorem states that if the complex number is a root of a polynomial f(x), then the complex conjugate is also a root of that polynomial.

in this problem we have that

is a root of the polynomial function f(x)

so

the complex conjugate is also a root of the function f(x)

therefore

the answer is the option A

50 min

step-by-step explanation:

they will be decreasing both their times in half

60 / 2 = 30

40/2 = 20

30 + 20 = 50