Question

x
$x {}^{2} - x - 20 = 0$
delta​

Answer 1

x² - x - 20 = 0

A= 1

B= - 1

C= - 20

∆= b² - 4ac

∆= ( - 1)² - 4 • 1 • ( - 20)

∆= 1 + 80

∆= 81

x= - b ± √∆ / 2a

x= - ( -1) ± √81/2 • 1

x= 1 ± 9/2

x'= 1 + 9/2 = 10/2 = 5

x''= 1 - 9/2 = - 8/2 = - 4

S= ( 5 , - 4)

Answer 2

resolução!

${x}^{2} - x - 20 = 0$

∆ = (-1)^2 - 4 * 1 * (-20)

∆ = 1 + 80

∆ = 81

X ' = 1 + √∆ / 2

X ' = 1 + √81/2

X ' = 1 + 9/2

X ' = 10/2

X ' = 5

X " = 1 - 9/2

X " = - 8/2

X " = - 4

S = { - 4 , 5 }