Question

x²-2x-9=0
ajudaaaa please please ​

Answer 1

Explicação passo-a-passo:

a= 1

b= -2

c= -9

∆= b² - 4.a .c

∆= (-2)² -4.1.(-9)

∆= 4 + 36

∆= 40

40 l 2

20 l 2

10 l 2

5 l 5

1

40= 2³.5= 2² . 2 .5

x = - b ±√∆/2.a

x= - (-2) ±√40 /2.1

x= +2 ±√40 /2

x= 2 ± √ 2².2.5/2

x= 2± 2.√10/2

x1= 2 + 2√10

________

2

x1 = 1 + √10

x2= 2 - 2√10

_______

2

x2= 1 - √10

S= { 1+√10 , 1 - √10}