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…