Absolute-Value Equations and Inequalities
Mental Math Solving
–Think What values could x be that would make the equation true? HINT: There are two!
–ANSWER: 5 or -5
Mental Math Solving (More Example)
• x = 7 or -7• x = 9 or -9• x = 18 or -18
Solving an Absolute-Value Equation
– This means that can equal 5 or -5.
x – 2 IS POSITIVE x – 2 IS NEGATIVE
SOLUTION: x = 7 or x = -3
Solving an Absolute-Value Equation
2x – 7 IS POSITIVE 2x – 7 IS NEGATIVE
POSITIVE NEGATIVE
IMPORTANT CHEAT SHEET
Solving Absolute-Value Equations and Inequalitiesax+b<c means ax+b<c AND ax+b>-cax+b≤c means ax+b≤c AND ax+b≥-cax+b=c means ax+b=c OR ax+b=-cax+b>c means ax+b>c OR ax+b<-cax+b≥c means ax+b≥c OR ax+b≤-c
Solving Absolute-Value Inequalities
• Remember that is the distance between and 0.• If , then any number between -8 and
8 is solution to the inequality.
x – 4 IS POSITIVE x – 4 IS NEGATIVE
Solution :1<x<7
2x + 1 IS POSITIVE 2x + 1 IS NEGATIVE
POSITIVE NEGATIVE
Homework Assignment
• Pg. 356 – 357–Numbers: 24 – 36 and 46 – 46
evens
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