Question

vertice da parabola com x2-2x-3

Answer 1

$f(x)=x^2-2x-3$

$a=1~~~~~~b=-2~~~~~~c=-3$

$x_{\text{V}}=\dfrac{-b}{2\cdot a}$

$x_{\text{V}}=\dfrac{-(-2)}{2\cdot1}~\hookrightarrow~x_{\text{V}}=\dfrac{2}{2}~\hookrightarrow~\boxed{x_{\text{V}}=1}$

$y_{\text{V}}=\dfrac{-\Delta}{4\cdot a}$

$\Delta=b^2-4\cdot a\cdot c$
$\Delta=(-2)^2-4\cdot1\cdot(-3)$
$\Delta=4+12$
$\Delta=16$

$y_{\text{V}}=\dfrac{-16}{4\cdot1}~\hookrightarrow~y_{\text{V}}=\dfrac{-16}{4}~\hookrightarrow~\boxed{y_{\text{V}}=-4}$

$\text{V}(1,-4)$