Question

Change y=x^2+6x=3 from parabola equation to vertex form

Answer 1

first divide 6 ( from 6x) by 2
and write (x+3)^2

x^2 + 6x - 3 = (x + 3)^2 - a - 3

x^2 + 6x must equal (x +3)^2 - a
so we need to find the value of a:

(x+3)^2 = x^2 + 6x + 9

so a must be 9

x^2 + 6x - 3 = (x+3)^2 - 9 - 3
= (x+3)^2 - 12

and that s vertex form