Question

calcule a soma dos quadrilateros das reaizes da equacao x2-3x-4=0

Answer 1

Resposta:

x² - 3x - 4 = 0

ax² + bx + c = 0

a = 1

b = - 3

c = - 4

S = ?

Resolvendo temos:

$x = \dfrac{- b \pm \sqrt{b^{2} - 4ac} }{2a} = \dfrac{+ 3 \pm \sqrt{(- 3 )^{2} - 4 \times 1 \times (-4)} }{2\times 1}$

$x = \dfrac{3 \pm \sqrt{9 + 16} }{2} = \dfrac{3 \pm \sqrt{25} }{2} = \dfrac{3 \pm 5 }{2}$

$x_1 = \dfrac{3 - 5 }{2} = \dfrac{ - 2 }{2} = - 1$

$x_2 = \dfrac{3 + 5 }{2} = \dfrac{ 8 }{2} = 4$

Calcular a soma:

$S = x_1 + x_2 = - 1 + 4 = 3$