How do you find the vertex of a parabola $y=(x+5)(x+3)$ ?

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Answer 1 · 2015-07-19T00:29:48

The vertex is at $color(red)((-4,-1)$ .

$y = (x+5)(x+3)$

$y = x^2+8x+15$

The standard form of the equation for a parabola is

$y = ax^2 + bx + c$

By comparing the two equations, we see that

$a = 1$ , $b = 8$ , and $c = 15$ .

The $x$ -coordinate of the vertex is at $x = -b/(2a) = -8/(2×1) = -8/2 = -4$ .

To find the $y$ -coordinate of the vertex, we insert $x = -4$ into the equation.

$y = (x+5)(x+3) = (-4+5)(-4+3) = 1(-1) = -1$

The vertex is at ( $-4,-1$ ).

Graph

How do you find the vertex of a parabola y=(x+5)(x+3)y=(x+5)(x+3)?