to a) (i), (ii)
The equation of a circle with the center is:
Use completing the square to transform the given equation into the general form:
If the circle crosses the x-axis then y = 0. Plug in this value into the given equation and solve for x.
The tangent is perpendicular to the line MP. Calculate the slope of MP, calculate the perpendicular slope, which is the slope of the tangent, use point-slope-formula of a straight line to get the equation of the tangent.