WAEC 2020 Mathematics · Question 29
If (x + 2) is a factor of x +px - 10, find the value of P.
Options
- A.3
- B.-3
- C.7
- D.-7
Answer: B. -3
Explanation written with AI and checked against the answer key
Analyze the question: We're told (x + 2) is a factor of x² + px − 10, and we need p. Concept (Factor Theorem): If (x − a) is a factor of f(x), then f(a) = 0. Here x + 2 = x − (−2), so a = −2 and f(−2) = 0. Solution: f(x) = x² + px − 10 f(−2) = (−2)² + p(−2) − 10 = 0 4 − 2p − 10 = 0 −2p − 6 = 0 −2p = 6 p = −3 Check: With p = −3, the expression is x² − 3x − 10. Factorising: (x − 5)(x + 2) = x² − 3x − 10 ✓. So (x + 2) is indeed a factor. Tip: For "(x + a) is a factor" questions, substitute x = −a (the sign flips) and set the expression equal to zero. Then check by factorising if time allows.AI can make mistakes. Report anything that looks wrong.
Past questions © the examination body (JAMB/WAEC/NECO). DeeepSolve is not affiliated with them. Rights holders: see /copyright.