Answer:
[tex]y=(x+4)^{2}-37[/tex]
Step-by-step explanation:
we know that
The equation of a vertical parabola into vertex form is equal to
[tex]y=a(x-h)^{2}+k[/tex]
where
(h,k) is the vertex of the parabola
if a> 0 then the parabola open upward (vertex is a minimum)
if a< 0 then the parabola open downward (vertex is a maximum)
In this problem we have
[tex]y=x^{2}+8x-21[/tex]
Convert to vertex form
Complete the square
[tex]y+21=x^{2}+8x[/tex]
[tex]y+21+16=(x^{2}+8x+16)[/tex]
[tex]y+37=(x^{2}+8x+16)[/tex]
[tex]y+37=(x+4)^{2}[/tex]
[tex]y=(x+4)^{2}-37[/tex] --------> equation in vertex form
The vertex is the point [tex](-4,-37)[/tex]
the parabola open upward (vertex is a minimum)
