This document contains a math lesson on solving linear inequations in 1 and 2 steps. It begins with a warm up on solving equations, then discusses isolating the variable by adding or subtracting the same quantity to both sides of an inequality. Examples are provided and students are asked to check their work. The document concludes with a summary of the key steps and an assignment.
1. Do Now
Hand in your worksheets which you completed
over the weekend.
Complete as much of the timetables worksheet
as you can and then glue it into your books.
You have 3 minutes
Friday, 29 August 2014
2.
3. By the end of this lesson, I will be able to solve 1-
step linear inequations
Complete the puzzle in your groups.
4. By the end of this lesson, I will be able to solve 1-
step linear inequations
Point check:
Take 4 pieces of paper, write your name at the top and the date.
Answer 1 question on each piece of paper.
This is a small test to see how much you know, so no talking or
copying.
1. 푛 + 5 > 8
2. 푎 − 1 >
−
1
3. 2푚 > −4
4.
푥
2
<
−
4
5. By the end of this lesson, I will be able to
solve 2-step linear inequations
To do this, we must be able to solve 2-step equations:
To warm up, try these:
1) 3 + 5푟 = −32
2)
푎
3
− 1 =
−
1
3)
푥−1
2
=
−
4
4)
−
1 + 5푟 = −21
5) 2 +
푥
6
= 3
6. By the end of this lesson, I will be able to solve
2-step linear inequations
4푏 + 2 ≤ 6
4푏 + 2 − 2 ≤ 6 − 2
4푏 ≤ 4
4푏
4
≤
4
4
푏 ≤ 1
Check: 4 × 1 + 2 ≤ 6
4 + 2 ≤ 6
6 ≤ 6
Read the equation
starting with the
unknown, and undo the
last thing that was done
before the ≤.
I have the correct
answer, 푏 ≤ 1
7. By the end of this lesson, I will be able to solve
2-step linear inequations
4푥 − 9 > 3푥 + 1
4푥 − 9 + 9 > 3푥 + 1 + 9
4푥 > 3푥 + 10
4푥 − 3푥 > 3푥 + 10 − 3푥
푥 > 10
Read the equation.
What do you notice?
Let’s collect like
terms first
How could you check that your answer is correct?
Discuss in your groups and be able to explain your
answer on the board.
8. By the end of this lesson, I will be able to solve
2-step linear inequations
What happens when we end up with a negative 푥?
Take a look at this:
2 < 4
If we multiplied both sides by -1, what happens?
−
−
2 <
4
But is
−
2 <
−
4 still true?
What could we do to make this true?
−
2 <
−
4
−
2 <
−
4
NO!!!
> Flip the sign
9. By the end of this lesson, I will be able to solve
2-step linear inequations
10. By the end of this lesson, I will be able to solve
2-step linear equations involving addition
Sometimes, you will have to do 2 steps instead of 1.
3푥 + 6 = 18
3푥 + 6 − 6 = 18 − 6
3푥 = 12
3푥
12
=
3
3
푥 = 4
Check: 3 × 4 + 6 = 12 + 6
= 18
I have the correct
answer, 푥 = 4
Try for yourself
Read the equation
starting with the
unknown, and undo the
last thing that was
done.
11. By the end of this lesson, I will be able to solve
2-step linear equations involving addition
Sometimes, the constant will come before an unknown.
4 + 2푥 = 20
4 + 2푥 − 4 = 20 − 4
2푥 = 16
2푥
16
=
2
2
푥 = 8
Check: 4 + 2 × 8 = 4 + 16
= 20
Read the equation,
starting with the
unknown, and undo the
last thing that was done.
I have the correct
answer, 푥 = 8
Try for yourself
12. By the end of this lesson, I will be able to solve
2-step linear equations involving addition
Sometimes, you will have to do 2 steps instead of 1.
2푏 + 5 = 21
2푏 + 5 − 5 = 21 − 5
2푏 = 16
2푏
16
=
2
2
푏 = 8
Check: 2 × 8 + 5 = 16 + 5
= 21
Read the equation
starting with the
unknown, and undo the
last thing that was
done.
I have the correct
answer, 푏 = 8
13. By the end of this lesson, I will be able to
solve 2-step linear inequations
To do this, we must be able to solve 2-step equations:
To warm up, try these:
1) 3 + 5푟 = −32
2)
푎
3
− 1 =
−
1
3)
푥−1
2
=
−
4
4)
−
1 + 5푟 = −21
5) 2 +
푥
6
= 3
14. By the end of this lesson, I will be able to solve
linear inequations
To be able to solve linear inequations, we must be able to
understand what these symbols mean and use them:
>
<
≥
≤
“greater than”
“less than”
“greater than or equal to”
“less than or equal to”
6 ____ 5
5 _____ 6
6 _____ 5
5 _____ 6
15. By the end of this lesson, I will be able to solve
linear inequations
Exercise 1:
Are these true or false?
16. By the end of this lesson, I will be able to solve
linear inequations
Exercise 2:
17. By the end of this lesson, I will be able to solve
linear inequations
To solve linear equations, we must be able to isolate the 푥 as we
have been doing and then make sure that our answer is correct.
푥 + 2 > 3
푥 + 2 − 2 > 3 − 2
푥 > 1
Q: When this was an
equals (=) symbol,
what were you doing?
Is 푥 + 2 > 3 when 푥 > 1?
What’s a number greater than 1?
Is this true? 2 + 2 > 3
4 > 3
A: Taking
away 2 from
both sides
Q: Now what would you do? A: Simplify
Q: Now what would you do? A: Check
A: 2
Yes, it’s true, therefore our
answer, 푥 > 1 is correct
18. By the end of this lesson, I will be able to solve
linear inequations
Try another:
푥 − 4 > 3
푥 − 4 + 4 > 3 + 4
푥 > 7
Q: When this was an
equals (=) symbol,
what were you doing?
Is 푥 − 4 > 3 when 푥 > 7?
What’s a number greater than 7?
Is this true? 8 − 4 > 3
4 > 3
A: Adding 4 to
both sides
Q: Now what would you do? A: Simplify
Q: Now what would you do? A: Check
A: 8
Yes, it’s true, therefore our
answer, 푥 > 7 is correct
19. By the end of this lesson, I will be able to
solve linear inequations.
Summary:
What did you learn today?
What are two mistakes your neighbour made
today?
Homework: page 26-28
Should have done: up to and including
page 21