Question

O zero da função f(x) = x² – 6x + 8 é? *

2 pontos

-4 e 2

4 e 2

4 e -2

-4 e -2

-4 e -4

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Answer 1

$x^2-6x+8=0\\\\\Delta=b^2-4.a.c\\\Delta=-6^2-4.1.8\\\Delta=36-32\\\Delta=4\\\\x=-\frac{b\pm\sqrt{\Delta}}{2a}\\\\x=\frac{6\pm\sqrt{4}}{2}\\\\x=\frac{6\pm2}{2}\\\\x_1=4\\x_2=2$