O-LevelAdditional MathematicsQuadratic functions4037/22 · Oct/Nov 2019 · Q45 Marks
Find the values of k for which the line y = kx+3 does not meet the curve y = x²+5x+12.
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2019). The mark or mark type is shown in brackets.
- M1 kx + 3 = x² + 5x + 12 → x² + (5 – k)x + 9(= 0) Equate and attempt to simplify to all terms on one side.
- M1 dep Use discriminant of their quadratic.
- A1 (5 – k)² – 36 oe Unsimplified
- A1 k = -1 and 11 Both boundary values
- A1 -1 < k < 11 Must be in terms of k.
- OR
- M1 2x+5~k Connect gradients of line and curve
- M1 Eliminate k and y.
- A1 x² = 9 → x = ± 3
- A1 k = 11 or k = -1
- A1 -1 < k < 11
Write your answer and get it marked
On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.
Sign up free →