Verified answer

A) x⁴ - 10x² + 9 = 0

y² - 10y + 9 = 0

Δ = b² - 4.a.c

Δ = (-10)² - 4.1.9

Δ = 100 - 36

Δ = 64

y = (-b ± √Δ)/2.a

y = (10 ± 8)/2

y' = 9

y" = 1

x² = 9

x = ± √9

x = ± 3

x² = ± √1

x = ± 1

Resposta: S = {-3,-1, 1, 3}

B) x⁴ - 25x² = 0

y² - 25y = 0

Δ = b² - 4.a.c

Δ = (-25)² - 4.1.0

Δ = 625

y = (-b ± √Δ)/2.a

y = (25 ± 25)/2

y' = 25

y" = 0

x² = ± √25

x² = ± 5

x² = 0

x = 0

Resposta: {-5, 0, 5}.