Question

As Raizes da funcao de 2° grau f (x) = -
${ \times }^{2}$
+×+2 Sao:

Answer 1

$f(x)=-x^2+x+2$

$-x^2+x+2=0$

$\Delta=1^2-4\cdot(-1)\cdot2$
$\Delta=1+8$
$\Delta=9$

$x=\dfrac{-1\pm\sqrt{9}}{2\cdot(-1)}=\dfrac{-1\pm3}{-2}$

$x'=\dfrac{-1+3}{-2}~\longrightarrow~x'=\dfrac{2}{-2}~\longrightarrow~\boxed{x'=-1}$

$x"=\dfrac{-1-3}{-2}~\longrightarrow~x"=\dfrac{-4}{-2}~\longrightarrow~\boxed{x"=2}$

As raízes são $-1$ e $2$.

Answer 2

Boa noite!

f(x) = - x² + x + 2 

f(x) = 0

- x² + x + 2 = 0 

Δ = 1² - 4.(-1).2

Δ = 1 + 8

Δ = 9 

x = - 1 + - √9 / 2.(-1)

x' = - 1 + 3 / - 2 

x' = 2 / - 2 

x' = - 1 

x" = - 1 - 3 / - 2 

x" = - 4 / - 2 

x" = 2 

Raízes: {- 1, 2}