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Solution - Absolute value equations

Exact form: a=12
a=\frac{1}{2}
Decimal form: a=0.5
a=0.5

Other Ways to Solve

Absolute value equations

Step-by-step explanation

1. 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
|a|=|a1|
without the absolute value bars:

|x|=|y||a|=|a1|
x=+y(a)=(a1)
x=y(a)=(a1)
+x=y(a)=(a1)
x=y(a)=(a1)

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||a|=|a1|
x=+y , +x=y(a)=(a1)
x=y , x=y(a)=(a1)

2. Solve the two equations for a

4 additional steps

a=(a-1)

Subtract from both sides:

a-a=(a-1)-a

Simplify the arithmetic:

0=(a-1)-a

Group like terms:

0=(a-a)-1

Simplify the arithmetic:

0=1

The statement is false:

0=1

The equation is false so it has no solution.

6 additional steps

a=-(a-1)

Expand the parentheses:

a=a+1

Add to both sides:

a+a=(-a+1)+a

Simplify the arithmetic:

2a=(-a+1)+a

Group like terms:

2a=(-a+a)+1

Simplify the arithmetic:

2a=1

Divide both sides by :

(2a)2=12

Simplify the fraction:

a=12

3. Graph

Each line represents the function of one side of the equation:
y=|a|
y=|a1|
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.