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Solution - Absolute value equations

Exact form: x=-133,-1
x=-\frac{13}{3} , -1
Mixed number form: x=-413,-1
x=-4\frac{1}{3} , -1
Decimal form: x=4.333,1
x=-4.333 , -1

Other Ways to Solve

Absolute value equations

Step-by-step explanation

1. Rewrite the equation with one absolute value terms on each side

|2x+7|+|x+6|=0

Add |x+6| to both sides of the equation:

|2x+7|+|x+6||x+6|=|x+6|

Simplify the arithmetic

|2x+7|=|x+6|

2. Rewrite the equation without absolute value bars

Use the rules:
|x|=|y|x=±y and |x|=|y|±x=y
to write all four options of the equation
|2x+7|=|x+6|
without the absolute value bars:

|x|=|y||2x+7|=|x+6|
x=+y(2x+7)=(x+6)
x=y(2x+7)=(x+6)
+x=y(2x+7)=(x+6)
x=y(2x+7)=(x+6)

When simplified, equations x=+y and +x=y are the same and equations x=y and x=y are the same, so we end up with only 2 equations:

|x|=|y||2x+7|=|x+6|
x=+y , +x=y(2x+7)=(x+6)
x=y , x=y(2x+7)=(x+6)

3. Solve the two equations for x

10 additional steps

(2x+7)=-(x+6)

Expand the parentheses:

(2x+7)=-x-6

Add to both sides:

(2x+7)+x=(-x-6)+x

Group like terms:

(2x+x)+7=(-x-6)+x

Simplify the arithmetic:

3x+7=(-x-6)+x

Group like terms:

3x+7=(-x+x)-6

Simplify the arithmetic:

3x+7=6

Subtract from both sides:

(3x+7)-7=-6-7

Simplify the arithmetic:

3x=67

Simplify the arithmetic:

3x=13

Divide both sides by :

(3x)3=-133

Simplify the fraction:

x=-133

8 additional steps

(2x+7)=-(-(x+6))

NT_MSLUS_MAINSTEP_RESOLVE_DOUBLE_MINUS:

(2x+7)=x+6

Subtract from both sides:

(2x+7)-x=(x+6)-x

Group like terms:

(2x-x)+7=(x+6)-x

Simplify the arithmetic:

x+7=(x+6)-x

Group like terms:

x+7=(x-x)+6

Simplify the arithmetic:

x+7=6

Subtract from both sides:

(x+7)-7=6-7

Simplify the arithmetic:

x=67

Simplify the arithmetic:

x=1

4. List the solutions

x=-133,-1
(2 solution(s))

5. Graph

Each line represents the function of one side of the equation:
y=|2x+7|
y=|x+6|
The equation is true where the two lines cross.

Why learn this

We encounter absolute values almost daily. For example: If you walk 3 miles to school, do you also walk minus 3 miles when you go back home? The answer is no because distances use absolute value. The absolute value of the distance between home and school is 3 miles, there or back.
In short, absolute values help us deal with concepts like distance, ranges of possible values, and deviation from a set value.