The line y=mx−2y = mx - 2y=mx−2 is a tangent to the circle x2+6x+y2−8y+5=0x^2 + 6x + y^2 - 8y + 5 = 0x2+6x+y2−8y+5=0.
Verify that the two possible values of m m\,m are 18±10511\displaystyle \frac{18 \pm 10\sqrt{5}}{11}1118±105.
292 exam-style questions on Edexcel A Level Maths Circles, covering 6.1 Midpoints and Perpendicular Bisectors, 6.2 Equation of a Circle, 6.3 Intersections of Straight Lines and Circles, 6.4 Use Tangent and Chord Properties, and 6.5 Circles and Triangles. Each one has a worked solution and a mark scheme showing where the marks go.