x² + 9 = 6x

x² - 6x + 9 = 0

Δ=(-6)²-4.1.9

Δ=36-36

Δ=0

x=(-(-6)+-√0)/2

x=(6+-0)/2

x'=x"=6/2 => 3

s= {3}

Conta com Delta e Bhaskara:

x² + 9 = 6x

x² - 6x + 9 = 0

Aplicamos Delta:

(-6)² - 4.1.9

36 - 36

Δ = 0

Aplicamos Bhaskara:

-(-6) +/- √0 / 2.1

6 +/- 0 / 2

x¹ = 6 + 0 / 2 = 3

x² = 6 - 0 / 2 = 3