Question

Verificar quais itens são raízes da equação f(x)=x² - 5x  + 6
a)2     b)5     c)3

Answer 1

$x^{2}-5x+6=0$

$a=1\\b=-5\\c=6$

$\Delta=b^{2}-4*a*c\\\Delta=(-5)^{2}-4*1*6\\\Delta=25-24\\\Delta=1$

$x = (-b\pm\sqrt{\Delta})/2a\\x=(-[-5]\pm\sqrt{1})/(2*1)\\x=(5\pm1)/2$

$x'=(5+1)/2\\x'=6/2\\x'=3$

$x''=(5-1)/2\\x''=4/2\\x''=2$

Raízes: 2 e 3, a) e c).