Enter an equation or problem

Camera input is not recognized!

Solution - Absolute value equations

Exact form:

x = \frac{7}{4}, - \frac{1}{10}

x=\frac{7}{4} , -\frac{1}{10}

Mixed number form:

x = 1 \frac{3}{4}, - \frac{1}{10}

x=1\frac{3}{4} , -\frac{1}{10}

Decimal form:

x = 1.75, - 0.1

x=1.75 , -0.1

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
$| 3 x + 4 | = | 7 x - 3 |$
without the absolute value bars:

$\| x \| = \| y \|$	$\| 3 x + 4 \| = \| 7 x - 3 \|$
$x = + y$	$(3 x + 4) = (7 x - 3)$
$x = - y$	$(3 x + 4) = - (7 x - 3)$
$+ x = y$	$(3 x + 4) = (7 x - 3)$
$- x = y$	$- (3 x + 4) = (7 x - 3)$

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:

$\| x \| = \| y \|$	$\| 3 x + 4 \| = \| 7 x - 3 \|$
$x = + y$ , $+ x = y$	$(3 x + 4) = (7 x - 3)$
$x = - y$ , $- x = y$	$(3 x + 4) = - (7 x - 3)$

2. Solve the two equations for x

11 additional steps

$(3 x + 4) = (7 x - 3)$

Subtract from both sides:

$(3 x + 4) - 7 x = (7 x - 3) - 7 x$

Group like terms:

$(3 x - 7 x) + 4 = (7 x - 3) - 7 x$

Simplify the arithmetic:

$- 4 x + 4 = (7 x - 3) - 7 x$

Group like terms:

$- 4 x + 4 = (7 x - 7 x) - 3$

Simplify the arithmetic:

$- 4 x + 4 = - 3$

Subtract from both sides:

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

Simplify the arithmetic:

$- 4 x = - 3 - 4$

Simplify the arithmetic:

$- 4 x = - 7$

Divide both sides by :

$\frac{(- 4 x)}{- 4} = \frac{- 7}{- 4}$

Cancel out the negatives:

$\frac{4 x}{4} = \frac{- 7}{- 4}$

Simplify the fraction:

$x = \frac{- 7}{- 4}$

Cancel out the negatives:

$x = \frac{7}{4}$

10 additional steps

$(3 x + 4) = - (7 x - 3)$

Expand the parentheses:

$(3 x + 4) = - 7 x + 3$

Add to both sides:

$(3 x + 4) + 7 x = (- 7 x + 3) + 7 x$

Group like terms:

$(3 x + 7 x) + 4 = (- 7 x + 3) + 7 x$

Simplify the arithmetic:

$10 x + 4 = (- 7 x + 3) + 7 x$

Group like terms:

$10 x + 4 = (- 7 x + 7 x) + 3$

Simplify the arithmetic:

$10 x + 4 = 3$

Subtract from both sides:

$(10 x + 4) - 4 = 3 - 4$

Simplify the arithmetic:

$10 x = 3 - 4$

Simplify the arithmetic:

$10 x = - 1$

Divide both sides by :

$\frac{(10 x)}{10} = \frac{- 1}{10}$

Simplify the fraction:

$x = \frac{- 1}{10}$

3. List the solutions

$x = \frac{7}{4}, - \frac{1}{10}$
(2 solution(s))

4. Graph

Each line represents the function of one side of the equation:
$y = | 3 x + 4 |$
$y = | 7 x - 3 |$
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. List the solutions

4. 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. List the solutions

4. Graph

Why learn this

Terms and topics

Related links

Latest Related Drills Solved