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Inequalities. Because “ I<3U ” does not mean “ I love you. ” Mathematically, it means I less than 3 of you. What is an inequality?. Mathematical sentence that compares quantities. To solve an inequality you have to find values for the variable that make the sentence true.
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Inequalities Because “I<3U” does not mean “I love you.” Mathematically, it means I less than 3 of you.
What is an inequality? • Mathematical sentence that compares quantities. • To solve an inequality you have to find values for the variable that make the sentence true. • Inequalities do not contain equal signs.
Translating sentences to inequalities • TIPS • Use a variable to represent the unknown • Look for key words to determine the inequality symbol you will use. • Example 1: We don’t know what the number is. We will use x to represent the unknown number. is greater than 2. A number x > 2
More Examples We don’t know what the number is. We will use x to represent the number. • Example 2: • Example 3: The maximum value of a number is 28. x ≤ 28 We don’t know what the number is. We will use x to represent the number. A number is greater than or equal to four. x ≥ 4
Graphing inequalities • Steps: • Draw a number line and place the number in the problem in the middle of the number line. • Fill in numbers on the number line. • Put a circle on the number 2 on the number line. • For this example, you leave the circle open (not colored in). • Shade in the part of the number line that shows the numbers that are greater than 2. • Example 1: x > 2 0 1 2 3 4
Examples with Graphing Inequalities -Both of these examples mean that the variable can be equal to the number in the inequality. -When you graph these inequalities, color in the circle. Example 2: x ≤ 28 Example 3: x ≥ 4