Question

Calcule com ∆=b²-4.a.c
X=-b±√∆
2.a
X²-3x-4=0

Answer 1

X² - 3x - 4 = 0

a = 1

b = (-3)

c = (-4)

Δ = -3² - 4*1*-4

Δ = 9 + 16

Δ = 25

X = --3 +/- √25 / 2*1

X = 3 +/- 5 / 2

x' = 3 + 5 = 8 / 2 = 4

x'' = 3 - 5 = -2 / 2 = -1

Espero ter ajudado :)

Answer 2

Resposta:

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

Explicação passo-a-passo:

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

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

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

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

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