Please help I am terrible at algebra

Equation of parabola is [tex]y=(x+10)^{2}[/tex].
Step-by-step explanation:
The vertex form of the parabola is given as, [tex]y=a(x-h)^{2}+k[/tex]
where (h,k) is the vertex of the parabola.
If the parabola must be symmetric about x = -10 then the axis of symmetry must be x = -10.
To execute this, h should be -10, and it was plugged in the vertex form of the parabola, a and k may be any real number.
So the equation can be written as, [tex]y=(x+10)^{2}[/tex]