Question

As raízes da equação x2-9x+18=0 sao ?

Answer 1

x² - 9x + 18 = 0

a = 1

b = - 9

c = 18

∆ = b² - 4 . a . c

∆ = (-9)² - 4 . 1 . 18

∆ = 81 - 72

∆ = 9

x = - b ± √∆

------------

2a

x' = - (-9) - 3

------------

2 . 1

x' = 9 - 3

-------

2

x' = 6

---

2

x' = 3

x" = - (-9) + 3

------------

2 . 1

x" = 9 + 3

-------

2

x" = 12

---

2

x" = 6

S = {3 , 6}