The equation of the parabola is: y = (3/441)x^2 + 21
Let's find the equation of the parabola going through (21, 21), (−21, 21), and (−20, −20).
We know that a parabola can be represented in the form of y = ax^2 + bx + c. To find the equation of the parabola that passes through the three given points, we can substitute the coordinates of each point into the equation and solve for a, b, and c.
Substituting (21, 21), we get:
21 = 441a + 21b + c
Substituting (-21, 21), we get:
21 = 441a - 21b + c
Substituting (-20, -20), we get:
-20 = 400a - 20b + c
Solving this system of equations, we get:
a = 3/441
b = 0
c = 21
Therefore, the equation of the parabola is: y = (3/441)x^2 + 21