use the information provided to write the vertex form equation of each parabola. vertex:(9, -3) focus:(9, -25/8)

Question

use the information

Answer 1

A parabola with its vertex at (9 , -3) has an equation y + 3 = a · (x - 9)² or y = a · (x - 9)² - 3

We can use the given focus to solve for a because a = 1/(4p) where p is the distance between the vertex and the focus. Note that for a vertically oriented parabola (like this one) we will call p negative if the focus is below the vertex (like this one).

p = - 1/8 ; a = -2 and y = -2(x - 9)² - 3