Post on 23-Sep-2020
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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
-3