Question

Considere a função y= -x2+2×+3

Answer 1

Resposta:

$-x^{2} +2x+3=0\\ \\ a=-1,b=2,c=3\\ \\ x=\frac{-b+-\sqrt{b^{2}-4.a.c } }{2.a} \\ \\ x=\frac{-2+-\sqrt{2^{2}-4.(-1).3 } }{-2} \\ \\ x=\frac{-2+-\sqrt{4+12} }{-2} \\ \\ x=\frac{-2+-\sqrt{16} }{-2} \\ \\ x=\frac{-2+-4}{-2} \\ \\ x'=\frac{-2-4}{-2} =\frac{-6}{-2} =+3\\ \\ x''=\frac{-2+4}{-2} =\frac{+2}{-2} =-1\\ \\ S\left \{ {{-1;} ~~{3}} \}$