Jack is 3 years older than his brother. How old are they if the sum of their ages is greater than 17? Write an inequality and solve. Represent the solution set on a number line.
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Khan Academy Inequalities on a Number Line
Guidance
When you solve a linear inequality you can represent your solution graphically with a number line. Your job is to show which of the numbers on the number line are solutions to the inequality.
When graphing solutions to inequalities, use an open circle to show that the number is not included as part of the solution and a closed circle to show that the number is included as part of the solution. The line above the number line shows all of the numbers that are possible solutions to the inequality.
Example A
Represent the solution set to the following inequality on a number line:
Solution:
Example B
Represent the solution set to the following inequality on a number line:
Solution:
Example C
Represent the solution set to the following inequality on a number line:
Solution:
Concept Problem Revisited
Jack is 3 years older than his brother. How old are they if the sum of their ages is greater than 17? Write an inequality and solve. Represent the solution set on a number line.
If first let’s write down what you know:
Let
Let
The equation would therefore be:
Therefore if Jack’s brother is 8 (since
Representing Jack's brother's age on a number line:
Guided Practice
1. Represent the solution set to the inequality
2. Represent the solution set to the inequality
3. Represent the solution set to the inequality
Answers:
1.
2.
3.
Explore More
Solve each inequality and represent the solution set on a number line.

−4v>12 
−2r3>4 
4(t−2)≤24 
12(x+5)>6 
14(g+2)≤2 
0.4(b+2)≥2 
0.5(r−1)<4 
14(x+16)>2 
2−k>5(1−k) 
2(1.5c+4)≤−1 
−12(3x−5)≥7 
0.35+0.10(m−1)<0.45 
14+23(t+1)>12  The prom committee is selling tickets for a fundraiser for the decorations. Each ticket costs $3.50. What is the least number of tickets the committee needs to sell to make $1000? Write an inequality and solve.
 Brenda got 69%, 72%, 81%, and 88% on her last four major tests. How much does she need on her next test to have an average of at least 80%? Write an inequality and solve.