2
49
158
1
α + β = λ - 3αβ = 2 - λα² + β² = (α + β)² - 2αβ = (λ - 3)² - 2(2 - λ) = λ² - 6λ + 9 - 4 + 2λ = λ² - 4λ + 5 = (λ - 2)² + 1Therefore, the least value occurs when λ = 2