Question

Resolva as equações do 2º grau:
a) x² – 3x – 4 = 0
b) x² + 8x + 16 = 0
c) 3x² – 2x – 1 = 0
d) x² – 2x = 0 S
e) 4x² – 2x + 1 = 0
f) 5x² + 4x – 1 = 0
g) x² - 16 = 0
h) 9x² – 6x + 1 = 0
i) x² - 2 x + 4 = 0
j) 2x² + x = 0
k) x² - 16 = 0
l) x² - 1 = 0
​

Answer 1

a) a=1 b=-3 c=-4

delta= D

D=b² - 4.a.c/ D=(-3)² - 4.1.-4

9 +16=25

Bhaskara

$x = \frac{ - b +/ - \sqrt{d} } {2.a} \\ x = \frac{ - ( - 3) +/ - \sqrt{25} }{2.1}$

$x¹ = \frac{3 + 5}{2} = 4$

${x}^{2} = \frac{3 - 5}{2} = - 1$

b) x² + 8x + 16 = 0

∆ = 8² - 4 · 1 · 16

∆ = 64 - 64

∆ = 0

x = - 8 ± √0 /2 · 1

x = - 8 ± 0 /2

x¹ = - 8 + 0/2 = - 8/2 = - 4

x² = - 8 - 0/2 = - 8/2 = - 4

S = { - 4 }