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,  

a28=58

step-by-step explanation:

a1=a1+(n-1)d

a28= 4+ (28-1)2

a28=4+(27)(2)

a28=4+54

a28=58