Question

Resolva equação do 2 grau
${ x}^{2} - 9 \times + 20 = 0$
​

Answer 1

x² - 9x + 20 = 0

a = 1

b = - 9

c = 20

Δ = b² - 4ac

Δ = 81 - 80

Δ = 1

√Δ = 1

x = ( - b ± √Δ) / 2a

x = (9 ± 1) / 2

x' = 10/2 = 5

x'' = 8/2 = 4

Reposta: 5 e 4

Answer 2

$Ola!!$

${\color{blue}{x^2-9x+20=0}}$

Onde:

$Coeficientes:\left\{\begin{array}{cc}a=1\\b=-9\\c=20\\\end{array}\right$

Lembrando que:

$\Leftrightarrow\Delta=b^2-4.a.c$

$\Leftrightarrow\Delta=(-9)^2-4.1.20$

$\Leftrightarrow\:\Delta=81-80$

${\color{blue}{\Leftrightarrow\Delta=1}}$

$\Leftrightarrow\large\boxed{\boxed{{x_{1}=\frac{-b\pm\sqrt{\Delta}}{2.a}}}}}}$

$\Leftrightarrow\:x_{1},_{2}=\frac{9\pm\sqrt{1}}{2.1}$

$\Leftrightarrow\:x_{1},_{2}=\frac{9\pm\:1}{2}$

$\Leftrightarrow\:x_{1}=\frac{9+1}{2}$

$\Leftrightarrow\:x_{1}=\frac{10}{2}$

${\color{blue}{\Leftrightarrow\:x_{1}=5}}$

$\Leftrightarrow\:x_{2}=\frac{9-1}{2}$

$\Leftrightarrow\:x_{2}=\frac{8}{2}$

${\color{blue}{\Leftrightarrow\:x_{2}=4}}$

$\underline{Espero\:Ter\:Ajudado}$