Question

-x ao quadrado -5x -4 = 0

Answer 1

-x² - 5x - 4 = 0   (multiplicando por -1)

x² + 5x + 4 = 0

Δ =(5)² - 4(1)(4)

Δ = 25 - 16 = 9

√Δ = √9 = 3

x' = (-5 + 3)/2 = -2/2 = -1

x'' = (-5 - 3)/2 = -8/2 = -4

Resposta: x = -1 ou x = -4

Espero ter ajudado.

Answer 2

Resposta:

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

Explicação passo-a-passo:

$-x^{2} -5x-4=0\:\times(-1)\\x^{2} +5x+4=0$

$a=1\\b=5\\c=4$

$\Delta=b^{2} -4ac\\\Delta=5^{2}-4\times1\times4\\\Delta=25-16\\\Delta=9$

$x=\frac{-b\pm\sqrt{Delta} }{2a} \\\\x=\frac{-5\pm\sqrt{9} }{2\times1} \\\\x=\frac{-5\pm3}{2}$

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