The equation x2+kx+(k+3)=0x^2 + kx + (k + 3) = 0x2+kx+(k+3)=0, where k k\,k is a constant, has different real roots.
Show that k2−4k−12>0k^2 - 4k - 12 > 0k2−4k−12>0.
Find the set of possible values of kkk.
Practise Edexcel A Level Old Maths Algebra and Functions 1 with exam-style questions for A Level Old Maths. 19 questions, matched to the Edexcel A Level Old Maths (9371) specification and written in Unit exams C1, C2, C3 and C4 plus two applied units (e.g. S1 and M1) style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.