How do you solve these problems?

1) find standard equation of circles that pass thru (2,3) and are tangent to both lines 3x-4y=-1 and 4x+3y=7

2 find standard eqations of circles that have centers on 4x+3y=8 and are tangent to both the line x+y=-2 and 7x-y=-6

3) find eqations of lines thru (4,10) and tangent to circle x^2+y^2-4y-36=0

these problems come at the beginning of calculus 1???? help!!!!!!!!