Answer
$\color{blue}{f(x)=x^2-6x+8}$
Work Step by Step
RECALL:
The zeros of the quadratic function $f(x) =(x+a)(x+b)=0$ are $x=-a$ and $x=-b$.
The given quadratic function has the zeros $x=2$ and $x=4$.
Using the rule mentioned in the recall part above, then the function is:
$f(x)=[x+(-2)][x+(-4)]
\\f(x)=(x-2)(x-4)
\\f(x)=x^2+x(-4) - 2(x) - 2(-4)
\\f(x)=x^2-4x-2x+8
\\\color{blue}{f(x)=x^2-6x+8}$
