Question

Resolva, em R, as equações a seguir:

B) (2x + 1) . (-4x² + 4x -1) = 0
D) (x + 5)² = (2x - 3)²
E) x³ + 10x² + 21x = 0

Answer 1

Boa noite Mkenz

B) (2x + 1) * (-4x² + 4x - 1) = 0

2x + 1 = 0
2x = -1
x = -1/2

4x² - 4x + 1 = 0

delta
d² = 16 - 16 = 0
d = 0

x = 4/8 = 1/2

S = (-1/2, 1/2)

D)

(x + 5)² = (2x - 3)²

x² + 10x + 25 = 4x² - 12x + 9
3x² - 22x - 16 = 0

delta
d² = 22² + 12*16 = 676
d  = 26 

x1 = (22 + 26)/6  = 48/6 = 8
x2 = (22 - 26)/6 = -4/6 = -2/3 

E) x³ + 10x² + 21x = 0

x*(x² + 10x + 21) = 0

x*(x + 7)*(x + 3) = 0

x1 = 0
x2 = -7
x3 = -3