Answer:
A
Step-by-step explanation:
Hello, I assume that the quadratic function f has real coefficients, so this is something like, a, b and c being real numbers
[tex]f(x)=ax^2+bx+c[/tex]
If a complex number z is a zero of f ( meaning solution of f(x)=0) then
[tex]\overline z[/tex] which is the conjugate of z is a zero too, because
[tex]\text{if } f(z)=0=az^2+bz+c \text{ then}\\\\\overline {f(z)}=0=a\overline z ^2 +b \overline z + c\\\\\text{meaning } f(\overline z)=0[/tex]
Here, we know that [tex]\sqrt{7}+5i[/tex] is a solution, so
[tex]\overline {\sqrt{7}+5i}= \sqrt{7}-5i[/tex] is a solution too.
Thank you
