Question

delta de x2 - x - 1 = 0

Answer 1

Resposta:

${x}^{2} - x - 1 = 0 \\ a = 1 \: \: b = - 1 \: \: c = - 1 \\ \\ d = {b}^{2} - 4 \times a \times c \\ d = {( - 1)}^{2} - 4 \times 1 \times ( - 1) \\ d = 1 + 4 \\ d = \sqrt{5}$

Answer 2

∆ = b^2 -4.a.c

∆= (-1)^2 -4.1.(-1)

∆ = 1 + 4

∆ = 5