Question

como resolver 2x + 8 = 10; 3x = 18 e x2 - 7x + 10 = 0?

Answer 1

$2x + 8 = 10$
$2x = 10 - 8$
$2x = 2$
$x = \frac{2}{2}$
$x = 1$

$3x = 18$
$x = \frac{18}{3}$
$x = 6$

$x^{2} - 7x + 10 = 0$
Δ = $b^{2} - 4ac$
Δ = $(-7)^{2} - 4.1.10$
Δ = $49 - 40$
Δ = 9

$x = \frac{-b+ ou- \sqrt{Δ} }{2a}$
$x = \frac{-(-7) + ou- \sqrt{9}}{2.1}$
$x = \frac{7+3}{2} =$
$x= 5$
$x = \frac{7-3}{2}$
$x = \frac{4}{2}$
$x = 2$

.: S = {5,2}