Part 2: Use the information provided to write the vertex form equation of each parabola.

1. Vertex: (1,4)
Focus: (7/8, 4)

2. Vertex: (5, 0)
Directrix: x = 21/4

3. Vertex: (-1, 2)
Directrix: y = 41/20

  1.  x = -2(y - 4)² + 1

                2.  x = -y² + 5

                3.  y = -5(x + 1)² + 2

Step-by-step explanation:

Notes: The vertex formula of a parabola is x = a(y - k)² + h  or  y = a(x - h)² + k

1)

Now input a = -2 and (h, k) = (1, 4) into the equation x = a(y - k)² + h

x = -2(y - 4)² + 1

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2)

Now input a = -1 and (h, k) = (5, 0) into the equation x = a(y - k)² + h

x = -1(y - 0)² + 5    →    x = -y² + 5

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3)

Now input a = -5 and (h, k) = (-1, 2) into the equation y = a(x - h)² + k

y = -5(x + 1)² + 2

∞ this is your sign