Second Term Lesson Note for Week Three.
Class : SSS 2
Subject : Mathematics
Topic : Linear Inequalities in variables
Duration : 80 Minutes
Period : Double Period
Reference Book :
- New General Mathematics for Senior Secondary Schools, Book 2. (SSS 2)
- Lagos State Unified schemes of work for Senior Secondary Schools, SSS 1 – 3.
- Online Resources
Instructional Material : Chart showing number lines and equation involving inequalities.
Learning Objectives : By the end of the lesson learners will be able to :
i. Explain inequalities and it signs
ii. Explain the concept of linear inequalities involving one variable
iii. Solve problems of linear inequalities in variables
Content :
REVISION OF LINEAR INEQUALITIES IN VARIABLE
The term inequality applies to any statement involving one of the symbols. Similar to ordinary equations, inequality equations too have solutions.
Rules for finding the solutions to inequality equations
- Add or subtract at the same expression or number to both sides of the inequality and preserve the inequality sign.
- Multiply or divide both sides of the inequality by the same positive number and preserve the inequality sign.
- Multiply or divide both sides of the inequality by the same negative number and reverse the inequality sign.
The expression 3x – 1 > x + 1 is a linear inequality in one variable x. Thus, a linear inequality in x is an inequality in which the highest power of x is one (unit).
Solve the following linear inequality and represent them on a number line.
A number line is used to illustrate linear inequalities in one variable. A point x = a divides the number line into 2 parts, x < a and x > a
But when x = a is included, the number line becomes
A line segment from a to be is denoted by a and it is shown below
4x + 8 < 3x + 16
Subtract 8 from both sides
4x + 8 – 8 < 3x – 8 + 16
4x < 3x + 8
Subtract 3x from both sides
4x – 3x < 3x + 8 – 3x
X < + 8
ii. 3 (x – 6)> 9 (x – 1)
open the brackets
3x – 18 > 9x – 9
Collect like terms
3x – 9x > -9 + 18
-6x > + 9
Divide through by -6 and change the sign.
X < – 9/6
X < – 3/2 or – 1 1/2
Evaluation :
1 . 5 (x + 2) – 2(4x -1) > 6(2x -3)
2. 3 – 3x < 6
3. (-1 < x < 3)
4. (2x + 7) – (1 – 4) < 4 + x
Conclusion : At the end of the lesson the students were able to answer the questions correctly.
ASSIGNMENT :
page 95 exercise C2 number 1 to 3