Question

One solution to a quadratic function, f, is given below.

√7 + 5i

Which of the following statements is true about the given function?

A.) The other solution to function f is -√7 + 5i .
B.) The other solution to function f is √7 - 5i .
C.) Function f has no other solutions.
D.) The other solution to function f is √7 - 5i.

Answer 1

The other solution is the conjugate of the given one, which means the sign in between the 2 "numbers" is the opposite of the one given. So our conjugate here is choice B.

Answer 2

Explanation:

Concept is that irrational and complex root of a polynomial always exist with it conjugate pair.

It means if a+ib is a root then a-ib must also be a root of the polynomial .

Now since √7 + 5i is a root then other root must be √7 - 5i

So the correct option is

B.) The other solution to function f is √7 - 5i .