9.5 Solving
Quadratic
Equations by
Graphing
Ms. Wu
• Place a sticky note on any three posters…
• RED – need most help
– need some help
• GREEN – good to go! 
Warm-Up
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Warm-Up (5 min.)
Reminder 101 (3 min.)
Review (10 min.)
Quiz, Evaluation, Folder Organization ( 27 min.)
• Introduction (5 min.)
• 9.5 Workshop (20 min.)
• In-Class Assignment (20 min.)
Objectives
Remind 101 – 3rd
th
Remind 101 – 4
Axis of Symmetry x = 2
Domain: all real numbers
y-int (0, 3)
Range: y ≥ -1
Opens UP
Zeros: 1 and 3
Review
Vertex (2, -1)
Minimum
For the parent function, y = x2, what is the
transformed function that is ____________?
• 7 units up: y = x2 + 7
• 2 times wider: y = ½x2
• 1/3 times narrower and down 1 unit: y = 3x2 – 1
Review
For the function, y = x2+2x-1, what is the ________?
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Axis of symmetry? x =
Vertex: (-1, -2)
Does it open up or down? UP
Is it a maximum or minimum? MINIMUM
y-intercept: (0, -1)
Domain: all real numbers
Range: y ≥ -1
Review
Quiz -> Evaluation - > Organization -> Lunch
Is your folder ready for an organization grade??
• Notes
• 9.1
• 9.2
• 9.3
• 9.4
• Roller Coaster
• 1st Blueprint
• 2nd Blueprint
• Homework
• 9.1
• 9.2
• 9.3
• 9.4
Everything must be
completed…folders will
be picked up for a grade
next class period!!
• In-Class
Assignments
• 9.2 Exploration
(Axis of
Symmetry)
• 9.4
Transformers
Exploration
• Go to Ms. Wu’s website: annwustudentteaching.webs.com
• Go to the tab “For Students (3rd & 7th)”
• New Format:
• Homework: Watch videos, take notes
• In-Class: Work on assignment, get help, quiz
Announcement
• A quadratic function is a function that can be written in
the standard form y = ax2+bx+c.
• A quadratic equation is an equation that can be written
in the standard form 0 = ax2+bx+c.
• When writing a quadratic function as its related quadratic
equation you replace y with 0. Then, you solve the
equation by finding its zero(s) or roots or x-int.
Solving Quadratic Equations by Graphing
Ms. Wu’s hint: Remember to move everything to
one side until you have everything equal to 0!
• Examples:
• 1. x2-8x-16=2x2 -x2-8x-16 = 0 zero: -4
• 2. 6x+10=-x2
x2+6x+10=0
• 3. –x2+4 = 0
zeros: -2, 2
zero: none
• Video: Parabolic Solar Ovens in Coast Rica
• Video: How to Cook Food Using Solar Ovens
Parabolic Solar Ovens
Joseph is trying to
build a solar oven in
his backyard to cut
down on the cost of
electricity. He did
some research and
found that the sun’s
rays are best captured
by the quadratic
function
y = x2 -8x+12.
Question: Joseph needs to buy a parabolic mirror at Lowe’s,
how wide should the diameter of the mirror be?
Mirror needs to be 4 feet in diameter.
• Complete the evens on 9-5. Turn in by
the end of class.
• Homework: complete notes on how to
FOIL and FACTOR. Watch videos
online. Organize folder!!
In-Class & Homework