steps: 

1. first compare the second equation x^2+y^2-4x-8y-5=0 with the eq of center of circle x^2+y^2+2gx+2fy+c=0 , compute the center of the circle that is (-g,-f)

hence here the center of circle is (2,4)

2. calculate the radius : Sqrt(g^2+f^2-c)= 5 units

if the line intersects circle at two points then the length of perpendicular from the center of circle must be less than radius of circle.

|3.2-4.4-t|/(sqrt)(3^2+4^2)< 5

on solving,

|t+10|<25

if |x|<a, then

-a<x<a

= -25<t+10<25

= -25-10<t+10-10<25-10

= -35<t<15 

hope you got it.