Question

encontre as raízes das equações .
${x }^{2} - 4x - 5 = 0$

Answer 1

$x^2-4x-5=0\\\\\Delta=(-4)^2-4\cdot(1)\cdot(-5)\\\Delta=16+20\\\Delta=36\\\\x=\frac{-(-4)\pm\sqrt36}{2\cdot1}\to x=\frac{4\pm6}{2}\\\\x'=\frac{4+6}{2}=5\\\\x''=\frac{4-6}{2}=-1\\\\s=\{-1,5\}$