Question

Dada a função f(x) = -x2 + 2.x – 1, determine as raízes reais.


x’ = -1


x’ = 1


x’ = 2


x’ = 3


x’ = 0

Answer 1

-x²+2x-1 = 0 então temos

a = -1
b = 2
c = -1

$\frac{-b+- \sqrt{ b^{2} -4.a.c}}{2.a} = \frac{-2+- \sqrt{ 2^{2} -4.(-1).(-1)}}{2.(-1)} =\frac{-2+- \sqrt{4 -4}}{-2} =\frac{-2+- \sqrt{0}}{-2}$

x' = $\frac{-2}{-2} = 1$