ե) x2 – 2x + 1 = 0 զ) x2 + 4x + 4 = 0
D = 22 – 4 · 1 = 4 – 4 = 0 D = 16 – 16 = 0
x1 = x2 x1 = x2
x1 + x2 = 2 x1 + x2 = -4
x1 · x2 = 1 x1 · x2 = 4
ե) L = 0, K = -9 զ) L = 4, K = 4
x2 + Lx + K = 0 x2 + Lx + K = 0
x2 + 0 · x – 9 = 0 x2 + 4x + 4 = 0
x2 – 9 = 0