Question

X ao quadrado - 7 = x + 5

Answer 1

x² - 7 = x + 5

x² - x - 7 - 5

x² - x - 12 = 0

a = 1

b = - 1

c = - 12

∆ = b² - 4 . a . c

∆ = (-1)² - 4 . 1 . (-12)

∆ = 1 + 48

∆ = 49

x = - b ± √∆

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

2a

x' = - (-1) + 7

----------

2 . 1

x' = 1 + 7

-------

2

x' = 8

---

2

x' = 4

x" = - (-1) - 7

----------

2 . 1

x" = 1 - 7

------

2

x" = - 6

---

2

x" = - 3

S = {(4 , -3)}