Question

quanto é
${ \times }^{4} - 7 { \times }^{2} + 12 = 0$
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Answer 1

 Vamos fatorar!

$x^4-7.x^2+12=0\\x^4-3.x^2-4.x^2+12=0\\x^2.(x^2-3)-4.(x^2-3)=0\\(x^2-4).(x^2-3)=0\\\\x^2-4=0\\x^2=4\\\\x'=+\sqrt{4}\\x'=2\\\\x''=-\sqrt{4}\\x''=-2\\\\x^2-3=0\\x^2=3\\\\x'=+\sqrt{3}\\x''=-\sqrt{3}$

 S = { -2, -√3, √3, 2}

Dúvidas só perguntar!