Given data:
The first function given is f(x)=2x + 8.
The second function given is h(x) = 2x-8.
The expression for t(x) is,
[tex]\begin{gathered} t(x)=f(x)\times h(x) \\ =(2x+8)\times(2x-8) \\ =4x^2-64 \end{gathered}[/tex]The x-intercepts are the points where y coordinate is zero.
[tex]\begin{gathered} 0=4x^2-64 \\ 64=4x^2 \\ x^2=16 \\ x=4,-4 \end{gathered}[/tex]The y-intercepts are the points where x coordinate is zero.
[tex]\begin{gathered} y=4(0)^2-64 \\ =-64 \end{gathered}[/tex]Thus, the zeroes of t(x) are 4, -4, the y-intercept of the graph is (0, -64) and t(x)=4x^2 -64.