Question

calcule o valor de x na equaçao do 2 grau x²menos 3x menos 4 igual a zero

Answer 1

Resposta:

x₁=4

x₂= -1

Explicação passo-a-passo:

fazendo baskhara

x²-3x-4=0

a=1

b= -3

c= -4

Δ=b²-4.a.c

Δ=(-3)²-4.1.(-4)

Δ=9+16

Δ=25

x= -b±√Δ/2.1

x= -(-3)±√25/2

x=3±5/2

x₁=3+5/2

x₁=8/2

x₁=4

x₂=3-5/2

x₂= -2/2

x₂= -1

Answer 2

Utilizando a Fórmula de Bhaskara, temos:

$a=1\\b=-3\\c=-4\\\\\Delta=b^2-4\cdot a\cdot c\\\Delta=(-3)^2-4\cdot1\cdot(-4)\\\Delta=9+16\\\Delta=25\\ \\x=\frac{-b\pm\sqrt{\Delta}}{2\cdot a}\\ \\x=\frac{-(-3)\pm\sqrt{25}}{2\cdot1}\\ \\x'=\frac{3+5}{2}=\frac{8}{2}=4\\ \\x''=\frac{3-5}{2}=-\frac{2}{2}=-1\\ \\ \\S=\{(4;\;-1)\}$

Bons estudos!