SOLVING EQUATIONS CONTAINING ABSOLUTE VALUE(S)

Note:

• if and only if

• if and only if a+b=3 or a+b=-3

• if any only if a+b=+(x+y) or a+b=-(x+y)

Solve for x in the following equation.

Example 4:

Either or

Step 1: Solve

Step 2: Solve

There are four real answers at 0.242810330952, 2.49034517802, and 0.146018458341. However all these answers may or may not be solutions. You must verify that your answers are the solutions to the original equation.

Step 4:Check the solutions:

Check by substituting 2.62082603268 in the original equation for x. If the left side of the equation equals the right side of the equation after the substitution, you have found the correct answer.

• Left Side:

• Right Side:

Since the left side of the original equation is equal to the right side of the original equation after we substitute the value 2.62082603268 for x, then is a solution.

Check the solution by substituting 0.242810330952 in the original equation for x. If the left side of the equation equals the right side of the equation after the substitution, you have found the correct answer.

• Left Side:

• Right Side:

Since the left side of the original equation is not equal to the right side of the original equation after we substitute the value -0.683959382319 for x, then is not a solution.

Check the solution by substituting 2.49034517802 in the original equation for x. If the left side of the equation equals the right side of the equation after the substitution, you have found the correct answer.

• Left Side:

• Right Side:

Since the left side of the original equation is not equal to the right side of the original equation after we substitute the value 2.49034517802 for x, then is not a solution.

Check the solution by substituting 0.146018458341 in the original equation for x. If the left side of the equation equals the right side of the equation after the substitution, you have found the correct answer.

• Left Side:

• Right Side:

Since the left side of the original equation is equal to the right side of the original equation after we substitute the value 0.146018458341 for x, then is a solution.

The solutions are 2.62082603268 and 0.146018458341.

You can also check your answer by graphing

The graph is formed by subtracting the right side of the original equation from the left side of the original equation. Note that the graph has two x-intercepts located at 2.62082603268 and .0.146018458341 This verifies the two solutions.

If you would like to test yourself by working some problems similar to this example, click on Problems.

If you would like to go back to the equation table of contents, click on Contents.

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