I'm assuming you mean
If the function is undefined at , it usually means a division by zero takes place. *hint*hint
If it strikes the x axis at 8, that means when f(x)=0, x=8, i.e.:f(8)=0
And if it strikes the y-axis at 1, that means that at x=0, f(x)=1, i.e. f(0)=1
Substitute the values and use the hints.