Question

Resolva as equações de 2º grau:

a) x2 - 8x + 12 = 0

b) x2 + 8x + 12 = 0

c) x2 - 11x + 30 = 0

Answer 1

A x²-8x+ 12 = 0

b²-4ac
64 - 4 . 1 . 12
64-48
delta = 16

-b+- raiz de delta / 2a

xi = 8+4 / 2  = 12/2 = 6
xii= 8-4/2 = 12/2 = 4

B
b²-4ac
64 - 4 . 1 . 12
64-48
delta = 16
 
xi = -8 + 4/2a   = -4/2 = -2
xi = -8 -4/2 = -12/2 = -6

C

delta: b²-4ac
121 - 4 . 1 . 30
121-120
delta = 1

-b+-raiz de delta / 2a

xi = 11 + 1 / 2 = 12/2 = 6
xii = 11-1/2 = 10/2 = 5

Espero ter ajudado!