A parabola is a mirror-symmetrical U-shape.
- The equation of the parabola is

- The focus is

- The directrix is

- The axis of the symmetry of parabola is:

From the question, we have:


The equation of a parabola is:

Substitute the values of origin and vertex in 



Collect like terms

Solve for a

Substitute the values of a and the vertex in 

The focus of a parabola is:

Substitute the values of a and the vertex in 




The equation of the directrix is:

So, we have:
----- the directrix
The axis of symmetry is:

We have:

Expand

Expand


A quadratic function is represented as:

So, we have:


Recall that:

So, we have:


This gives


Hence, the axis of the symmetry of parabola is: 
Read more about parabola at:
brainly.com/question/21685473
Answer:
H
Step-by-step explanation:
This is because a rectangle can be divided into two triangles.
Keeping in mind that 16 = 2*2*2*2, thus 16 = 2⁴
Answer:
18.9
Step-by-step explanation:
21+(-3)-(-0.9) = 21-3+0.9 = 18+0.9 = 18.9