What is the vertex of the parabola $y = 4 x - x^{2}$ $y=4x-x^2$ ?

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Answer 1 · 2016-03-17T05:37:01

Vertex is $(- 2, - 4)$ $(-2, -4)$

Given -

$y = 4 x - x^{2}$ $y=4x-x^2$

We shall rewrite it as -

$y = x^{2} + 4 x$ $y=x^2+4x$

X- co-ordinate of the vertex is -

$x = \frac{- b}{2 a} = - \frac{4}{2} = - 2$ $x=(-b)/(2a)=-4/2=-2$

Y - co-ordinate at $x = - 2$ $x=-2$

$y = {(- 2)}^{2} + 4 (- 2)$ $y=(-2)^2+4(-2)$
$y = 4 - 8 = - 4$ $y=4-8=-4$

Its vertex is -

$(- 2, - 4)$ $(-2, -4)$

What is the vertex of the parabola y=4x−x2y=4x-x^2?