Finding a point of intersection between circles
My teacher has us going through these A level problems, but I am just so lost with this one. She said there may be a pop quiz tomorrow with similar questions, so i'd really like to get the concepts down flat. Would anyone be willing to explain how to solve the following word problem?
A) The circles (x^2)+(y^2)=20 and ((x-6)^2)+((y-3)^2)=5 are tangent. Find the coordinates of the point of trangency and then find an equation of the common internal tangent shown.
B) If you subtract the equations of the two circles from each other, you get a linear equation. Find this quation. Compare it with the quation found in part A.
Any help is appreciated. Thank you!