Algebra 1 : How to solve absolute value equations

Study concepts, example questions & explanations for Algebra 1

varsity tutors app store varsity tutors android store

Example Questions

Example Question #71 : How To Solve Absolute Value Equations

Solve:  

Possible Answers:

 

Correct answer:

 

Explanation:

First isolate the absolute value sign.  We will need to split the absolute value sign into its positive and negative components.

Divide by three on both sides.

Simplify both sides.

Eliminate the absolute value and solve.

Add two on both sides.

This is one solution.  

To find the other solution, break up the absolute value sign and add a negative sign in front of the left quantity.  The equation becomes:

Divide by negative one on both sides to move the negative sign to the other side.

Add two on both sides.

The solutions to this absolute value are:  .

Example Question #71 : How To Solve Absolute Value Equations

Solve:  

Possible Answers:

Correct answer:

Explanation:

In order to solve, we will need to separate the absolute value in its positive and negative components:

Solve the first equation.  Add three on both sides.

This is the first solution.

Solve the second equation.  Divide by negative one on both sides to move the negative sign to the right side.

Add three on both sides.

Simplify both sides.

The solutions are:  

Be careful not to enclose these two answers using interval notation because this problem is not an inequality and does not have a range of solutions!

Example Question #73 : How To Solve Absolute Value Equations

Which of the following is equivalent to  if  is less than 85?

Possible Answers:

None of the other responses is correct.

Correct answer:

Explanation:

If , it follows that . It further follows that 

and

.

Example Question #71 : How To Solve Absolute Value Equations

Which of the following is equivalent to  if  is greater than 75?

Possible Answers:

None of the other responses is correct.

Correct answer:

None of the other responses is correct.

Explanation:

If , then . It follows that 

and

None of the choices are equivalent to this expression.

Example Question #75 : How To Solve Absolute Value Equations

Give the solution set of the equation 

Possible Answers:

The equation has no solution.

Correct answer:

Explanation:

It follows that either  or ; we solve both separately.

 

 

 

The solution set is .

Example Question #71 : How To Solve Absolute Value Equations

Which of the following is equivalent to  if  is greater than 13?

Possible Answers:

None of the other responses is correct.

Correct answer:

Explanation:

If , then , and 

.

Therefore, 

Example Question #77 : How To Solve Absolute Value Equations

Which of the following is equivalent to  if  is less than 45?

Possible Answers:

None of the other responses is correct.

Correct answer:

Explanation:

If , then , and 

Therefore, 

Example Question #78 : How To Solve Absolute Value Equations

Which of the following is equivalent to  if  is less than 65?

Possible Answers:

None of the other responses is correct.

Correct answer:

Explanation:

If , it follows that

.

Since the expression between the abosolute value bars is negative, it follows that

and 

 

Example Question #71 : How To Solve Absolute Value Equations

Solve for x. 

Possible Answers:

 and 

 and 

 and 

Correct answer:

 and 

Explanation:

To solve for  we set up the two equations.

 and 

For the first equation 

And for the second equation

And so the solutions are

 and 

Example Question #71 : How To Solve Absolute Value Equations

Solve: 

Possible Answers:

Correct answer:

Explanation:

Break up the absolute value and rewrite the equation in its positive and negative components.

Solve the first equation. Start by adding four on both sides.

Simplify.

Divide by three on both sides.

This is one of the solutions.

Solve the second equation. Start by dividing a negative one on both sides.

Simplify both sides.

Add four on both sides.

Simplify both sides.

Divide by three on both sides.

The answer for this equation is:

The answers to this absolute value equation are: 

Learning Tools by Varsity Tutors