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OAU Post-UTME Mathematics 2013 Question 22

Question 22

Quadratic Equations

if ρ, λ are the roots of equation x2 − 5x + 7 = 0, find the value of ρ2 + λ2

  1. A.25
  2. B.−25
  3. C.−11
  4. D.11
Show the answer and explanation

Answer: D (11)

Explanation

ρ + λ = 5 and ρλ = 7. ρ² + λ² = (ρ + λ)² − 2ρλ = 25 − 14 = 11.