5.1 (Day 3)Graph Quadratic

Functions in vertex form

Goal: To graph quadratic functions written in vertex form and to write quadratic equations in standard form.

(F.IF.7a)

Previously, we graphed a quadratic that was in standard form. Standard form:

Another useful form of a quadratic function is vertex form:

y = a ( x - h )2 + k

• The graph of y = a(x - h)2 + k is the parabola y = ax2 translated

• horizontally h units • vertically k units

Vertex form of a quadratic equation: f(x) = a(x - h)2 + k:

• Vertex:

• Axis of symmetry:

• Graph opens:

For each quadratic function, give the vertex and axis of symmetry.

1. y = -4(x + 1)2 + 5 Vertex: _________ Axis of Symm: _____

2. f(x) = 2(x - 3)2 + 4 Vertex: _________ Axis of Symm: _____

3. y = (x - 9)2 Vertex: _________ Axis of Symm: _____

4. Graph. y = 2(x - 3)2 - 4 opens: UP or DOWN

vertex: __________

axis of sym: ________

max/ min value: ______

5. Graph f(x) = -(x + 3)2 - 1

opens: UP or DOWN

vertex: __________

axis of sym: ________

max/ min value: ______

6. Graph f(x) = -x2 + 4

opens: UP or DOWN

vertex: __________

axis of sym: ________

max/ min value: ______

Write the quadratic function in standard form. ( hint ** FOIL **)

7. y = (x - 6)2 + 8 8. f(x) = - 4(x - 7)2 + 2

Exit Problem:

Assignment: 5.1 Day 3 Worksheet

Do #2 on Wksht I must see it before you leave!!!!

5.1 Day 3 Answers

(2 , -1)x = 2

-1y = -x2 + 4x - 5

(-3, 4)x = -3

4f(x) = -2x2 - 12x - 14

(-4, -5)x = -4

-5y = 3x2 + 24x + 43

(-1,-8)

x = -1-8

y = x2 + 2x - 7

(4, 0)x = 4

0y = -1/2x2 + 4x - 8

(2, -3)x = 2

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