The line y=3nxy=3nxy=3nx intersects the curve y=x2+(n+1)x+3y=x^2+(n+1)x+3y=x2+(n+1)x+3 at two distinct points, where n n\,n is a constant.
Find the set of possible values for nnn, giving your answer in set notation.
8 exam-style questions on OCR A Level Maths 1.2.4 Quadratic functions. Each one has a worked solution and a mark scheme showing where the marks go.