What is the vertex form of $y=(x + 7)(x + 3)$ ?

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Answer 1 · 2016-10-17T19:19:16

The vertex form is $y=(x+5)^2-4$

$y=(x+7)(x+3)=x^2+10x+21=x^2+10x+25-4$
$y=(x+5)^2-4$
The vertex is at $x=-5$ which is also a line of symmetry
and the vertex is at $(-5,-4)$

graph{x^2+10x+21 [-10, 10, -5, 5]}

What is the vertex form of y=(x + 7)(x + 3) y=(x + 7)(x + 3) ?