A-LevelMathematicsAlgebra9709/21 · Oct/Nov 2022 · Q14 Marks
Solve the inequality |2x – 5| > x.
- Solve the inequality |2x – 5| > x.[4]
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2022). The mark or mark type is shown in brackets.
- [B1] Solve 2x-5=x to obtain x=5
- [M1] Attempt solution of linear equation where signs of 2x and x are different
- [A1] Obtain x=2/3
- [A1] Conclude x<2/3, x>5 (Must be 2 separate inequalities. Allow equivalents (-∞, 2/3) U (5,∞).)
- [B1] State or imply non-modulus equation (2x-5)² = x²
- [M1] Attempt solution of 3-term quadratic equation
- [A1] Obtain 2/3 and 5
- [A1] Conclude x<2/3, x>5 (Must be 2 separate inequalities. Allow equivalents (-∞, 2/3) U (5,∞).)
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