Question

 Dada a função f(x) = - x² - 3.x + 4 , determine as raízes da função. *

– 1 e 4

-4 e -1

-4 e 1

n.d.a


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Answer 1

Resposta:

-4 e 1

Explicação passo-a-passo:

$-x^2-3x+4=0\\\\a=-1//b=-3//c=4 \\\\\frac{-b+-\sqrt{b^2-4ac}}{2a}=\\\frac{3+-\sqrt{(-3)^2-4.(-1).4} }{2.(-1)}= \\\frac{3+-\sqrt{9+4.4}}{-2}=\\\frac{3+-\sqrt{9+16}}{-2}=\\\frac{3+-\sqrt{25}}{-2}=\\\frac{3+-5}{-2}=\\\\x_1=\frac{3+5}{-2}=\frac{8}{-2}=-4\\x_2=\frac{3-5}{-2}=\frac{-2}{-2}=1$