Precalculus : Inequalities and Linear Programming

Study concepts, example questions & explanations for Precalculus

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Example Questions

Example Question #1 : Solve Absolute Value Inequalities

Solve the following inequality: 

Possible Answers:

Correct answer:

Explanation:

First we need to get the expression with the absolute value sign by itself on one side of the inequality. We can do this by subtracting two from both sides then dividing everything by three.

Since absolute value signs make both negative and positive values positive we need to set up a double inequality.

Now to solve for  subtract four from each side.

Example Question #7 : Linear Inequalities

Solve for :

Possible Answers:

Correct answer:

Explanation:

If , then either or based on the meaning of the absolute value function. We have to solve for both cases.

a) subtract 5 from both sides

divide by -2, which will flip the direction of the inequality

 

Even if we didn't know the rule about flipping the inequality, this answer makes sense - for example, , and .

 

b) subtract 5 from both sides

divide by -2, once again flipping the direction of the inequality

Example Question #1 : Solve Absolute Value Inequalities

Solve the absolute value inequality.

Possible Answers:

Correct answer:

Explanation:

First, simplify so that the absolute value function is by itself on one side of the inequality.

.

Note that the symbol flipps when you divide both sides by .

Next, the two inequalities that result after removing the absolute value symbols are

 and   .

When you simplify the two inequalities, you get 

 and .

Thus, the solution is 

.

Example Question #41 : Inequalities And Linear Programming

Possible Answers:

Correct answer:

Explanation:

To solve absolute value inequalities, you have to write it two different ways. But first, divide out the 4 on both sides so that there is just the absolute value on the left side. Then, write it normally, as you see it:  and then flip the side and make the right side negative: . Then, solve each one. Your answers are and .

Example Question #842 : Pre Calculus

Solve the following:

Possible Answers:

Correct answer:

Explanation:

To solve absolute value inequalities create two functions.

Simply remember that when solving inequalities with absolute values, you keep one the same and then flip the sign and inequality on the other.

Thus,

Then, you must write it in interval notation.

Thus,

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