chapter 7 lesson 4 solving inequalities by adding or subtracting pgs. 345-349 what you’ll learn:...
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Chapter 7 Lesson 4Solving Inequalities
by Adding or Subtracting
pgs. 345-349
Chapter 7 Lesson 4Solving Inequalities
by Adding or Subtracting
pgs. 345-349
What you’ll learn:Solve inequalities by using the Addition or
Subtraction Properties of Inequality
What you’ll learn:Solve inequalities by using the Addition or
Subtraction Properties of Inequality
Solving an inequality means finding values for the variable that make the inequality true.
You can solve inequalities by using the Addition and Subtraction Properties of Inequalities (pg. 345) This is the same concept as using the Addition/Subtraction Properties of Equations (Lesson 3-3 pgs. 110-111)
Solving an inequality means finding values for the variable that make the inequality true.
You can solve inequalities by using the Addition and Subtraction Properties of Inequalities (pg. 345) This is the same concept as using the Addition/Subtraction Properties of Equations (Lesson 3-3 pgs. 110-111)
Example 1: Solving an Inequality using Subtraction
Example 1: Solving an Inequality using Subtraction
Solve -13 9 + b Check your solutionSolve -13 9 + b Check your solution
Write the inequality: -13 9 + b
Subtract 9 from each side: -13 9 + b -9 -9
Simplify: -22 b or b -22To check your solution, try any number less than or equal
to -22
Check using -22:-13 9 + (-22)-13 -13
Check: using -30-13 9 + -30-13 -21
Check using -20:-13 9 + -20-13 -11
Example 2: Solving an Inequality using AdditionExample 2: Solving an
Inequality using Addition
Solve a - 5 6 Check your solution Solve a - 5 6 Check your solution
Write the inequality: a - 5 6
Add 5 to both sides: a - 5 6 +5 +5
Simplify: a 11
Check your result by using any number greater than 11
Check using 12:12 - 5 67 6
Check using 32:32 - 5 627 6
Check using 7:7 - 5 62 6
Example 3: Graph Solutions of Inequalities
Example 3: Graph Solutions of Inequalities
Solve h + 4 4 Then graph the solution on a number line.
Solve h + 4 4 Then graph the solution on a number line.
Write the inequality: h + 4 4Subtract 4 from each side: h + 4 0
- 4 -4 h 0
The solution is h 0
Check: any number greater than 0I’m using 11 + 4 4 5 4
Now graph the solutionOn a number line.
Done on board in class.
Example 4: Use an Inequality to Solve a
Problem
Example 4: Use an Inequality to Solve a
ProblemChris is saving money for a ski trip. He
has $62.50, but his goal is to save at least $100. What is the least amount Chris needs to save to reach his goal?
Chris is saving money for a ski trip. He has $62.50, but his goal is to save at least $100. What is the least amount Chris needs to save to reach his goal?
Explore: We need to find the least amount Chris needs to savePlan: Let x represent the amount he needs to save. Write
an inequality to represent the problem. Remember at least means greater than or equal to.
x + 62.50 100
Solve: x + 62.50 100 - 62.50 -62.50 x 37.50
So the least amount that Chrisneeds to save is $37.50
Your Turn! Solve the inequality, graph your solution, do a check
Your Turn! Solve the inequality, graph your solution, do a check
A. c - (-2) 3
B. 25 n + (-12)
C. g - 1 2
D. k + 9 -21
A. c - (-2) 3
B. 25 n + (-12)
C. g - 1 2
D. k + 9 -21
2 3
16
c + 2 3 Check using -1 -2 -2 -1 - (-2) 3 c 1 13
25 n + (-12) Check using 40+12 +12 25 40 + (-12) 37 < n , n 37 25 28
g - 5 + 5 13 + 5 Check using 4 3 3 6 3 4 - 1 2 g 3
2 2
23
16
13
16k + 9 -21 Check using -25
- 9 -9 -25 + 9 -30 k -30 -16 -30
56
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