Question

How do you complete the square to rewrite y= x^ -6x + 15 in vertex form

Answer 1

Vertex form of a quadratic equation is $y=a(x-h)^{2}+k$
where (h, k) is the vertex. 

Our aim is to write the expression $y=x^{2} -6x+15$ in the form 
$y=a(x-h)^{2}+k$



$y=x^{2} -6x+15$

$y=x^{2} -2*3*x+15$

$y=(x^{2} -2*3*x+ 3^{2})-3^{2}+ 15$

$y=(x-3)^{2}-9+15$

$y=(x-3)^{2}+6$