Question

Resolva a equação do2° grau x2-3x-4

Answer 1

a= 1 b= -3 c= -4

∆= b²-4ac

∆= (-3)²-4(1)(-4)

∆= 9+16

∆=25

$x = \frac{ - b± \sqrt{∆} }{2a}$

$x = \frac{ -( - 3)± \sqrt{25} }{2.(1)}$

$x = \frac{3±5}{2}$

${x}^{i} = \frac{3 + 5}{2} \\ {x}^{i} = \frac{8}{2} \\ x^{i} = 4$

${x}^{ii} = \frac{3 - 5}{2} \\ {x}^{ii} = \frac{ - 2}{2} \\ {x}^{ii} = - 1$