Question

g(x)= x² - 10x + 9

Answer 1

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g(x)=x² -10x +9

x²-10x +9=0   equação do 2° grau

a=1
b=-10
c=9

Δ=b²-4ac
Δ=(-10²-4(1)(9)
Δ=100-36
Δ=64

$x= \frac{-b\pm \sqrt{\triangle} }{2a} ~= \frac{~-(-10)\pm \sqrt{64} }{2} ~= \frac{~10\pm8}{2} \\ \\ x'= \frac{10+8}{2} = \frac{18}{2} =9 \\ \\ x"= \frac{10-8}{2} = \frac{2}{2} =1 \\ \\ S=\{1,9\}$