Question

Fatorando a expressão x² + 4x + 3, temos
a) (x + 4) (x + 3)
b) (x + 3) (x + 1)
c) (x + 1) (x – 3)
d) (x + 12) (x + 1)
e) (x + 1) (x + 4)

Answer 1

y = x² + 4x + 3
0 = x² + 4x + 3
a = 1 / b = 4 / c = 3

x = [-b ± √(b² - 4ac)]/2a
x = [-4 ± √(4² - 4.1.3)]/2.1
x = [-4 ± √(16 - 12)]/2
x = [-4 ± √4]/2
x = [-4 ± 2]/2
x = -2 ± 1

x' = -2 + 1 = -1
x'' = -2 - 1 = -3

y = a(x - x')(x - x'')
y = 1(x - (-1))(x - (-3))
y = (x + 1)(x + 3)

Alternativa B.