Question

equações de 2º grau
x² - 3x - 4 = 0

Answer 1

x² - 3x - 4 = 0
x = 3 +- 5/2
x' = 4
x" = - 1

S = { 4 ; - 1 }

Answer 2

Resposta:

$S=\{-4,1\}$

Explicação passo-a-passo:

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

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

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

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

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