Question

Am nevoie urgenttttt!!!
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Answer 1

Răspuns:

Explicație pas cu pas:

f(x) = x^2 - 3x + 1

1 + f(x) = 0

x^2 - 3x + 1 + 1 = 0

x^2 - 3x + 2 = 0

Δ = 9 - 8 = 1

x1 = (3 + 1)/2 = 2

x2 = (3 - 1)/2 = 1

______________

x^2 - 3x + 1 = 0

Δ = 9 - 4 = 5

x1 = (3 + √5)/2

x2 = (3 - √5)/2

x1/x2 + x2/x1 = (x1^2 + x^2)/x1x2

x1^2 = (9 + 6√5 + 5)/4 = (14 + 6√5)/4

x2^2 = (9 - 6√5 + 5)/4 = (14 - 6√5)/4

x1x2 = (3 + √5)(3 - √5)/4 = (9 - 5)/4 = 4/4 = 1

(x1^2 + x^2)/x1x2 = (14 + 6√5)/4 + (14 - 6√5)/4 = 14/4 + 6√5/4 + 14/4 - 6√5/4

= 28/4 = 7