1. It is a circle with the centre C(-2, 1) and the radius 5.
2. The radius is perpendicular to the tangent in the tangent point. Thus the radius has the slope -4/3 and has to pass the centre:
Calculate the intersection of this line and the circle and you'll get the tangent points:
. After a few transformation you get:
. Solve for x. Plug in the values into the equation of the straight line r. The tangent points are:
3. You know the slope of the tangent and one point of the tangent. Use the point-slope-formula.