Question

x2 – 3x – 4 = 0 (é x ao quadrado, menos três x, menos quatro)

Answer 1

$x^{2} - 3x -4 = 0\\\\a=1\\b=-3\\c=-4\\\\x=\frac{-b\pm\sqrt{\Delta} }{2a}\\\\\Delta =b^{2} -4.a.c\\\Delta=(-3)^{2} -4.1.-4\\\Delta=9+16\\\Delta=25\\\\x=\frac{-b\pm\sqrt{\Delta} }{2a} \\\\x=\frac{3\pm5}{2.1} \\\\x=\frac{3\pm5}{2} \\\\x'=3+5.2=\frac{8}{2} = 4\\x''=3-5.2=-\frac{2}{2} =-1 \\\\S =\{-1,4 \}$

Answer 2

Resposta ↓

Conjunto solução ⇒ s = {4 ,1}

Explicação passo-a-passo:

EXPRESSÃO :

x² - 3x - 4 = 0

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Coeficientes :

a = 1

b = - 3

c = - 4

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Δ = b² - 4.a.c

Δ = (-3)² - 4.1.(-4)

Δ = 9 + 16

Δ = 25

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$x = \cfrac{-b\pm\sqrt{\Delta} }{2.a} \\\\\\x = \cfrac{-(-3)\pm\sqrt{25} }{2.1} \\\\\\x = \cfrac{3\pm5}{2} \\\\\\x' = \cfrac{3 + 5}{2} \\\\\\x' = \cfrac{8}{2} \\\\\\x' = 4\\\\\\x" = \cfrac{5 - 3}{2} \\\\\\x" = \cfrac{2}{2} \\\\\\x" = 1$

s = {4, 1}