Please help I am terrible at algebra

Equation of parabola is .

Step-by-step explanation:

The vertex form of the parabola is given as,

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,  

inverse operation of addition