Question

dada a função f(x)=x²-2x-3,calcule x para f(x)=-4

Answer 1

f(x)=-4
-4=x²-2x-3
0=x²-2x-3+4
0=x²-2x+1

$x= \frac{-(-2) \\ ^ - \\ {+} \sqrt{(-2)^{2} -4.1.1} }{2.1}$
$x= \frac{2 \\ ^ - \\ {+} \sqrt{4 -4} }{2}$
$x= \frac{2 + 0}{2}$
$x= \frac{2}{2} = 1$
ou
$x= \frac{2 - 0}{2}$
$x= \frac{2}{2} = 1$

x=1