Question

Quais são as raízes da equação x²-3x-4=0?

Answer 1

x² - 3x - 4 = 0

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

Delta:
Δ = b² - 4ac
Δ = (-3)² - 4 * 1 * (-4)
Δ = 9 + 16
Δ = 25
      Bhaskara:
      x = - b ± √Δ / 2a
      x = - (-3) ± √25 / 2 * 1
      x = 3 ± 5 / 2
      x' = 3 - 5 / 2 = -2 / 2 = -1
      x'' = 3 + 5 / 2 = 8 / 2 = 4

S = {-1, 4}

Espero ter ajudado. Valeu!

Answer 2

Resposta:

S = {- 1, 4}

Explicação passo-a-passo:

$x^{2} -3x-4=0$

$a=1\\b=(-3)\\c=(-4)$

$\Delta=b^{2} -4ac\\\Delta=(-3)^{2} -4\times1\times(-4)\\\Delta=9+16\\\Delta=25$

$x=\frac{-b\pm\sqrt{\Delta} }{2a} \\\\x=\frac{-(-3)\pm\sqrt{25} }{2\times1} \\\\x=\frac{3\pm5}{2}$

$x_{1} =\frac{3+5}{2} =\frac{8}{2} =4\\\\x_{2} =\frac{3-5}{2} =-\frac{2}{2} =-1$