Download Direct Instruction Model

Direct Instruction Model
Teacher: Theresa Cojohn
Lesson:1-4 Solving Absolute Value Equations
Subject: Algebra Students will engage in:
II
independent activities
cooperative learning
visuals
Date:
peer tutoring
simulations
pairing
9/17/2007
hands-on
whole group instruction
centers
Block: A & B
a project
technology integration
lecture
other:
Standards/Objectives Met: Each student will learn how to evaluate expressions involving
absolute values. Each student will be able to solve absolute value equations.
Time
Procedure Followed
Materials/Text
References
10
Class Starter: Solve the following equations for x.
minutes
1. 4r=3tx
2. 2x-9h=A
11
3.
 7t
3x
5
minutes
15
mintues
10
minutes
30
minutes
10
mintues
Review of Previously Learned Material/Homework: In lesson
1-3 student wrote expression and solved equations. In this
lesson, they apply those skills to equations involving absolute
value. Begin the lesson by reviewing what absolute value is and
then move to combining this knowledge with that of solving
equations.
Statement of Objectives: Each student will learn how to
evaluate expressions involving absolute values. Each student will
be able to solve absolute value equations.
Presentation of New Material: Begin with the idea of absolute
value. This is the distance a number is away from zero. So, x  a
Overhead notes
positive number, then x can be +/- the number. Then to solve an
equation using absolute value, you must solve twice. In Case 1, set
eh equation equal like normal. In case two set the equation equal
to the negative. Remember – you must check you work! If the
solution does not work then we use the empty set or {} or 0. Show
student that you must distribute the negative over the whole
equation. Also if there is a number in front of the bracket,
distribute.
Guided Practice: pg 30 #5-12 Check your work!
Glenco
Independent Practice: pg 30-31 #17-43 odd
Wrap Up/Lesson Review: Put the work on the board and
remind students of the two situations that need to be solved when
you see an absolute value.
Present Closure
Homework Given:1-4 Skills Practice odds
Test/Quiz Date: Friday 9/21/2007
Teacher Notes:
Glenco
Objective: Students will be able to solve equations involving absolute value and
inequalities involving absolute value.
The absolute value x of a number is its distance away from zero.
This means that the absolute value of any number is always _________________.
When solving absolute value equations, you must solve for both a  b and a  b .
You must always isolate the absolute value before solving!
Example: Solve for all value of x. Express your answer using set notation.
1. x  18  5
4. x  6  3x  2
2. -32x - 5 = -45
5. 4 3x - 5 +12 = 8
3. 6x  7 10  39
How do we solve an absolute value inequality?
 Write the problem without the absolute value sign, and solve the inequality.
 Write the problem without the absolute value sign, reverse the inequality,
negate the value NOT under the absolute value, and solve the inequality.
x <a
x<a
x > -a
If the symbol is < (or <) : (and)
Also written: - a < x < a.
x>a
x> a
If the symbol is >(or ≥) : (or)
Also written: x <- a or x>a.
6. x  5
7.
9.
2x  4
10.
8.
2x  3  6
x < -a
2x  5  5
3 x  1  9