Question

PRECISO DA RESPOSTA URGENTE

2-USANDO A FÓRMULA DISCRIMINANTE RESOLVA AS SEGUINTES EQUAÇÕES:

a) x ²-4x-5=0
b) x ²+2x-8=0

Answer 1

$x^2-4x-5 \\ \\ x= \frac{4+ \sqrt{16+4.1.5} }{2} \\ \\ x_{1} = \frac{4- \sqrt{16+4.1.5} }{2} \\ \\ x= \frac{4+ \sqrt{36} }{2}= \frac{4+6}{2} = 5 \\ \\ x_{1} = \frac{4- \sqrt{36} }{2}= \frac{4-6}{2} = \frac{-2}{2} =-1 \\ \\ \\ x^2+2x-8=0 \\ \\ x= \frac{-2+ \sqrt{4+4.1.8} }{2} \\ \\ x_{1} = \frac{-2- \sqrt{4+4.1.8} }{2} \\ \\ x= \frac{-2+ \sqrt{36} }{2}= \frac{-2+6}{2} =2 \\ \\ x_{1} = \frac{-2- \sqrt{36} }{2}= \frac{-2-6}{2} =-4$