Solving Inequalities Using Addition and Subtraction

Definitions• The solution of an inequality is the set of

numbers that make it true.

• There are four signs:

, , ,and

Key Words

< less than, fewer than, below > greater than, more than, above, exceeding ≤ less than or equal to, at most, not above ≥ no less than, at least, no fewer than

Let’s look at a coupleTrue or false (hands up for true, no hands for false) :

5 2 2 4

10 7

14 8 15 16

12 12

Ex. 1

7 3x

Now we graph it

• > and < are open circles

• are closed circlesand

x > -4

0 5 10510

In your notes

9 7x

0 5 10510

Again

10 4x

0 5 10510

Ex 2

• To get an A in class, Jack needs at least 1000 points. He has already earned 360 points. How many more points does he need for an A?

Closure

• Working with a partner, write and solve an inequality:

• Mark is saving up for an xbox. It costs $360 and he has already saved up $100. How much more does he need?