Helpful hints to help you with Graphs of Quadratic Functions
foldable and Quadratic Equations Matching Activity
Use your foldable on page 18 and angry birds warm-up on page 28.
A
B
C
D G
H
I
E
F
1
2
3
4 7
8
9
5
6
Hints:1.Factor the quadratic equation to find the roots.2.Find the roots on the graph.3. Use foldable on pg. 18 to help.
I will do problem #1 as an example on the next slide.
x2 – 3x – 4 = 0(x – 4)(x + 1) = 0 x = 4 x = -1
roots
8
x = -1 x = 4
Work shown on page 31 - 32
How to find the axis of symmetry?Use the axis of symmetry formula
x = 1.5
y = x2 – 3x – 4y = (1.5)2 – 3(1.5) – 4y = -6.25
Vertex: (1.5, -6.25)
How to find the Vertex?Substitute “x” into the quadratic equation to get “y”
Look at the foldable on page 18 to help
(1.5, -6.25)
(1.5, -6.25)x = 1.5
Hints:1.Find the roots on the graph.2. Work backwards to get the equation.Use angry birds warm-up on pg. 28 and foldable on page 18 to help
I will do problem #3 as an example on the next slide.
x = 0 x = 2
{0, 2}
(1, -1)
(1, -1)
x = 1
x = 1
Min (lowest point)(0, 0)
x = 0 x = 2x(x – 2) = 0x2 – 2x = 0
Equation needs to be in standard form y = ax2 + bx + c
y = x2 – 2x (check with graphing calculator…I know, so much work )
y = x2 – 2x Letter E roots are in between so use the equation strips to help you find the answer. It’s like a puzzle…