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-| x-4| + 2 = -2x + 7
Determine the real solution and the extraneous solution of the absolute value
equation.

Respuesta :

X=3

Let's solve your equation step-by-step.

|

x

4

|

+

2

=

2

x

+

7

Step 1: Add -2 to both sides.

|

x

4

|

+

2

+

2

=

2

x

+

7

+

2

|

x

4

|

=

2

x

+

5

Step 2: Divide both sides by -1.

|

x

4

|

1

=

2

x

+

5

1

|

x

4

|

=

2

x

5

Step 3: Solve Absolute Value.

|

x

4

|

=

2

x

5

We know either

x

4

=

2

x

5

or

x

4

=

(

2

x

5

)

x

4

=

2

x

5

(Possibility 1)

x

4

2

x

=

2

x

5

2

x

(Subtract 2x from both sides)

x

4

=

5

x

4

+

4

=

5

+

4

(Add 4 to both sides)

x

=

1

x

1

=

1

1

(Divide both sides by -1)

x

=

1

x

4

=

(

2

x

5

)

(Possibility 2)

x

4

=

2

x

+

5

(Simplify both sides of the equation)

x

4

+

2

x

=

2

x

+

5

+

2

x

(Add 2x to both sides)

3

x

4

=

5

3

x

4

+

4

=

5

+

4

(Add 4 to both sides)

3

x

=

9

3

x

3

=

9

3

(Divide both sides by 3)

x

=

3

Check answers. (Plug them in to make sure they work.)

x

=

1

(Doesn't work in original equation)

x

=

3

(Works in original equation)