The center of the circle (1, 2) and the radius R=√5,
Then the distance from the center of the circle to the straight line d = │1+4-5+√ 5 │/√ (1+4) =1,
∴(AB/2)^2+d^2=R^2,
(AB/2) 2+ 1 = 5,AB=4。
2, the straight line is (3x-y+3)a+(x+y+ 1)=0,
When 3x-y+3=0 and x+y+ 1)=0, x=- 1, y=0,
That is, the straight line passes through the (-1, 0) point.
(- 1) 2+0+4 * (- 1) =-3 < 0,
The point (-1, 0) is in the garden.
So straight lines and circles intersect.