Enter an equation or problem

Camera input is not recognized!

Solution - Absolute value equations

Exact form:

x = \frac{3}{8}

x=\frac{3}{8}

Decimal form:

x = 0.375

x=0.375

See steps

Step-by-step explanation

1. Rewrite the equation without absolute value bars

Use the rules:
$| x | = | y |$ → $x = \pm y$ and $| x | = | y |$ → $\pm x = y$
to write all four options of the equation
$| 4 x | = | 4 x - 3 |$
without the absolute value bars:

$\| x \| = \| y \|$	$\| 4 x \| = \| 4 x - 3 \|$
$x = + y$	$(4 x) = (4 x - 3)$
$x = - y$	$(4 x) = - (4 x - 3)$
$+ x = y$	$(4 x) = (4 x - 3)$
$- x = y$	$- (4 x) = (4 x - 3)$

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:

$\| x \| = \| y \|$	$\| 4 x \| = \| 4 x - 3 \|$
$x = + y$ , $+ x = y$	$(4 x) = (4 x - 3)$
$x = - y$ , $- x = y$	$(4 x) = - (4 x - 3)$

2. Solve the two equations for x

4 additional steps

$4 x = (4 x - 3)$

Subtract from both sides:

$(4 x) - 4 x = (4 x - 3) - 4 x$

Simplify the arithmetic:

$0 = (4 x - 3) - 4 x$

Group like terms:

$0 = (4 x - 4 x) - 3$

Simplify the arithmetic:

$0 = - 3$

The statement is false:

$0 = - 3$

The equation is false so it has no solution.

6 additional steps

$4 x = - (4 x - 3)$

Expand the parentheses:

$4 x = - 4 x + 3$

Add to both sides:

$(4 x) + 4 x = (- 4 x + 3) + 4 x$

Simplify the arithmetic:

$8 x = (- 4 x + 3) + 4 x$

Group like terms:

$8 x = (- 4 x + 4 x) + 3$

Simplify the arithmetic:

$8 x = 3$

Divide both sides by :

$\frac{(8 x)}{8} = \frac{3}{8}$

Simplify the fraction:

$x = \frac{3}{8}$

3. Graph

Each line represents the function of one side of the equation:
$y = | 4 x |$
$y = | 4 x - 3 |$
The equation is true where the two lines cross.

How did we do?

Please leave us feedback.

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.

Solution - Absolute value equations

Step-by-step explanation

1. Rewrite the equation without absolute value bars

2. Solve the two equations for x

3. Graph

Why learn this

Terms and topics

Related links

Solution - Absolute value equations

Step-by-step explanation

1. Rewrite the equation without absolute value bars

2. Solve the two equations for x

3. Graph

Why learn this

Terms and topics

Related links

Latest Related Drills Solved