I am trying to calculate the equation of line tangent to 2 circles. I have attached a picture to give a better idea.

Circle 1 has a center at (3,4) and radius of 5

Circle 2 has a center at (9,19) and radius of 11,

So far I have wrote the equation = of the 2 circles, and found the distance between the points the tangent lines touch on each circle.

My picture is not the most acurate one, it is just to give an idea.

Thanks for the help