1. Writing Quadratic Functions in Intercept Form
7.2 Part 2
Writing Quadratic Functions in Intercept Form

2. Example: Just like vertex form, find ____.
Write a quadratic function for the parabola shown.
SOLUTION
Use intercept form because the x-intercepts are given.
y = a(x – p)(x – q)
Intercept form
Find a.
Rewrite equation with all values, leaving x and y as variables in the EQ. 1 2 –
(x + 1)(x – 4)
y =

3. GUIDED PRACTICE
for Examples 1, 2 and 3
Write a quadratic function whose graph has the given characteristics.
1. vertex: (4, –5)
passes through: (2, –1)
y = (x – 4)2 – 5
2. vertex: (–3, 1)
passes through: (0, –8)
y = (x + 3)2 + 1
3. x-intercepts: –2, 5
passes through: (6, 2) 1 4
y = (x + 2)(x – 5)

4. Homework
See Agenda