Question

resolva as equação do 2° grau e encontre o valor da variavel x: a)x2-5×+6=0 b) x2-7×+6=2×-2

Answer 1

a) x² - 5x + 6 = 0

a = 1; b = -5 ; c = 6

Δ = b² - 4 . a . c
Δ = (-5)² - 4 . 1 . 6
Δ = 25 - 24
Δ = 1

x₁ = - b + √Δ / 2 . a
x₁ = - (-5) + √1 / 2 . 1
x₁ = 5 + 1 / 2
x₁ = 6 / 2 
x₁ = 3

x₂ = -b - √Δ / 2 . a
x₂ = -(-5) - √1 / 2 . 1
x₂ = 5 - 1 / 2
x₂ = 4 / 2
x₂ = 2

b) x² - 7x + 6 = 2x - 2
x² - 7x + 6 - 2x + 2 = 0
x² - 9x + 8 = 0

a = 1 ; b = - 9 ; c = 8

Δ = b² - 4 . a . c
Δ = (-9)² - 4 . 1 . 8
Δ = 81 - 32
Δ = 49

x₁ = - b + √Δ / 2 . a
x₁ = -(-9) + √49 / 2 . 1
x₁ = 9 + 7 / 2
x₁ = 16 / 2
x₁ = 8

x₂ = - b - √Δ / 2 . a
x₂ = -( -9) - √49 / 2 . 1
x₂ = 9 - 7 / 2
x₂ = 2 / 2
x₂ = 1