The correct option is A Both A and R are true and R is the correct explanation of A.
Assertion : x+2y−3=0 is a tangent to circle x2+y2−4x−6y+8=0 then from (2, 3) distance of x+2y−3=0 is equal to radius.
∴√5=∣∣∣2+6−3√5∣∣∣=∣∣√5∣∣
that means, x+2y−3=0 is a tangent of Given circle.
Reason (R): If lines is tangent to circle, then perpendicular djistance of line from the centre of circle is the radius of the circle.
then both A and R are True and R is the correct explanation of A.