Question

Resolva as equações do 2o grau utilizando a fórmula de Bháskara

a) x2- 5x + 6 = 0 b) x2- 18x = - 45

Answer 1

Resposta:

Explicação passo a passo:

1) $x^2-5x+6=0$

(I) Δ = $b^2-4ac = (-5)^2-(4*1*6)$

Δ = 25 - 24 ---> Δ = 1

(II) x = (-b ±√Δ)/2a

x = (5 ±√1)/2

x = (5 ±1)/2

(III)

x1 = (5 - 1)/2 = 4/2 ---> x1 = 2

x2 = (5 + 1)/2 = 6/2 ---> x2 = 3

2) $x^2-18x=-45\\x^2-18x+45=0$

(I) Δ = $b^2-4ac = (-18)^2-(4*1*45)$

Δ = 324 - 180 ---> Δ = 144

(II) x = (-b ±√Δ)/2a

x = (18 ±√144)/2

x = (18 ±12)/2

(III)

x1 = (18 - 12)/2 = 6/2 ---> x1 = 3

x2 = (18 + 12)/2 = 30/2 ---> x2 = 15