Question

Dada a equação de 2° grau encontre as ´possíveis raízes: ( 5x^2- 8x- 4 ) = 0 *
a) ( -2, 2/5 )
b) ( 2, - 2/5 )
c) ( -2, - 2/5)
d) Nenhuma das alternativas​

Answer 1

$\left(5x^2-8x-4\right)=0\\\\\left(5x+2\right)\left(x-2\right)=0\\\\5x+2=0\quad \mathrm{or}\quad \:x-2=0\\\\5x+2-2=0-2\\\\\frac{5x}{5}=\frac{-2}{5}\\\\x=-\frac{2}{5}$

$x-2=0\\\\x-2+2=0+2\\\\x=2\\\\x=-\frac{2}{5},\:x=2$

2, -2/5 ------- LETRA B