Question

Considerando m e n as raizes da equação x² - 7x + 12 = , qual o valor de ( m +n . (m . n )

Answer 1

Resposta:

x² - 7x + 12 = 0

a = 1

b = - 7

c = 12

$x = \dfrac{- b \pm\sqrt{b^{2} - 4ac} }{2a} = \dfrac{- (-7) \pm\sqrt{(-7)^{2} - 4\times 1 \times 12} }{2\times 1}$

$x = \dfrac{+7 \pm\sqrt{49 -48}}{2} = \dfrac{+7 \pm\sqrt{1}}{2} = \dfrac{+7 \pm{1}}{2}$

$x_1 = \dfrac{+7+1}{2} = \dfrac{8}{2} = 4$

$x_2 = \dfrac{+7 -1}{2} = \dfrac{6}{2} = 3$

m + n = 4 + 3 = 7

m$\times$ n = 4$\times$ 3 = 12