Question

como resolvo :x²-3x-4=0 na formula de bhaskara

Answer 1

x²-3x -4 = 0

a = 1

b= -3

c = -4

x = -b±√b² -4.a.c / 2.a


x= -(-3)±√3²-4.1.(-4) / 2.1


x = +3 ±√9 + 16 /2

x = +3 ±√25/2

x' = +3 +5 /2

x' = 8/2

x' =4

x" = +3 +5/2

x" = -2/2

x" = -1

raízes

x' = 4

x" = -1

Answer 2

Resposta:

S = {- 1, 4}

Explicação passo-a-passo:

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

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

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

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

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