Question

Qual o calculo e resultado de x²-9x+20=0

Answer 1

$x^{2} -9x+20$

Fórmula de Bhaskara: $\frac{-b+-\sqrt{b^{2}-4.a.c } }{2.a}$

$a=1\\b=-9\\c=20$

$\frac{-(-9)+-\sqrt{(-9)^{2}-4.1.20 } }{2.1}$  ⇒  $\frac{9+-\sqrt{81-80} }{2}$  ⇒  $\frac{9+-\sqrt{1} }{2}$  ⇒  $\frac{9+-1 }{2}$

+: $\frac{9+1}{2} = \frac{10}{2} =5$

-: $\frac{9-1}{2} = \frac{8}{2} =4$

S = {5, 4}

Answer 2

Explicação passo-a-passo:

a= 1

b= -9

c= 20

∆= b² - 4.a .c

∆= (-9)² - 4.1.20

∆= 81 - 80

∆= 1

x= -b ±√∆/2.a

x= - (- 9) ±√1/2.1

x= 9 ±1/2

x1= 9+1/2= 10/2= 5

x2= 9-1/2= 8/2= 4

S= { 4, 5}