Question

Dada a Função f:IR IR definida por f(x) = x²-4x-12, determine a raiz de f 

Answer 1

$x^2-4x-12=0 \\ \Delta=(-4)^2-4.1.(-12) = 16+48=64 \\ \\ x_1=\frac{4-\sqrt{64}}{2}=\frac{4-8}{2}=-2 \\ \\ x_2=\frac{4+\sqrt{64}}{2}=\frac{4+8}{2}=6$