Question

determine a raiz de y = - x ^ 2 + 2x + 15 =​

Answer 1

Resposta:

y = - x² + 2x + 15

- x² + 2x + 15 = 0

a = - 1                b = 2                  c = 15

Δ = b² - 4 * a * c

Δ = 2² - 4 * (- 1) * 15

Δ = 4 + 60

Δ = 64

x = - b ± √Δ  

        2 * a

x = - 2 ± √64  

      2 * (- 1)

x = - 2 ± 8  

        - 2

x' = (- 2 + 8) : (- 2)

x' = 6 : (- 2)

x' = - 3

x" = (- 2 - 8) : (- 2)

x" = - 10 : (- 2)

x" = 5

Raízes da equação: {- 3; 5}

Explicação passo-a-passo:

Answer 2

Olá!

$y=-x^{2} +2x+15\\ \\a=-1~~~,~~~b=2~~~,~~~c=15\\ \\ \\ \\ \\ \dfrac{-b\pm\sqrt{b^{2}-4\cdot a\cdot c } }{2\cdot a}~~ \to ~~~\dfrac{-2\pm\sqrt{2^{2}-4\cdot (-1)\cdot 15 } }{2\cdot (-1)} ~~~\to ~~\dfrac{-2\pm\sqrt{~64 } }{-2}\\ \\ \\ \\ \dfrac{-2\pm8 }{-2}~=~-\dfrac{6}{2}~~~\to~~ ~\boxed{x'=-3}$

$\dfrac{-10}{-2}~~=~~ \boxed{x''=5}$

Resposta:

Raízes:

x' = - 3

x'' = 5

:)