Question

y=x2-7x+12= ? como faço pra fazer essa conta (não entendo nada )

Answer 1

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$y= x^{2} -7x+12 \\ x^{2} -7x+12=0 \\ \\ x=- \frac{b\pm \sqrt{b^2-4ac} }{2a} \\ \\ x= \frac{-(-7)\pm \sqrt{(-7)^2-4(1)(12)} }{2} \\ \\ x= \frac{7\pm \sqrt{49-48} }{2} \\ \\ x= \frac{7\pm \sqrt{1} }{2} = \frac{7\pm1}{2}$

$x'= \frac{7+1}{2} = \frac{8}{2} =4 \\ \\ x"= \frac{7-1}{2} = \frac{6}{2} =3$

$V=\{3,4\}$