Question

x^2-11×+28=0 alguém sabe?

Answer 1

$x = \frac{-b \pm \sqrt{b^2-4.a.c}}{2.a}$

$x =\frac{-(-11) \pm \sqrt{(-11)^2-4.1.28}}{2.1}$

$x =\frac{11 \pm \sqrt{121-112}}{2}$

$x =\frac{11 \pm \sqrt{(9}}{2}$

$x =\frac{11 \pm 3}{2}$



$x' = \frac{11 + 3}{2}$

$x' = \frac{14}{2}$

$x' = 7$



$x'' = \frac{11 - 3}{2}$

$x'' = \frac{8}{2}$

$x'' = 4$