Question

Bagaimana penyelesaian dari gambar soal ini. tolong caranya ..

Answer 1

x² - kx + k - 1=0    x₁² + x₂² = 10
x₁ + x₂ = -b/a = -(-k)/1 = k
x₁x₂ = c/a = (k - 1)/1 = k-1
(x₁ + x₂)² = x₁² + 2x₁x₂ + x₂²
(x₁ + x₂)² = (x₁² + x₂²) + 2(x₁x₂)
    (k)²     =     (10)      + 2(k - 1)
    k²       =      10       + 2k - 2
k² - 2k - 8 = 0
(k - 4)(k + 2)
k=4 ∧ k = -2   [A]