Enter an equation or problem

Camera input is not recognized!

Solution - Absolute value equations

Exact form:

k = - 7, - \frac{3}{7}

k=-7 , -\frac{3}{7}

Decimal form:

k = - 7, - 0.429

k=-7 , -0.429

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
$| 4 k + 5 | = | 3 k - 2 |$
without the absolute value bars:

$\| x \| = \| y \|$	$\| 4 k + 5 \| = \| 3 k - 2 \|$
$x = + y$	$(4 k + 5) = (3 k - 2)$
$x = - y$	$(4 k + 5) = - (3 k - 2)$
$+ x = y$	$(4 k + 5) = (3 k - 2)$
$- x = y$	$- (4 k + 5) = (3 k - 2)$

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:

$\| x \| = \| y \|$	$\| 4 k + 5 \| = \| 3 k - 2 \|$
$x = + y$ , $+ x = y$	$(4 k + 5) = (3 k - 2)$
$x = - y$ , $- x = y$	$(4 k + 5) = - (3 k - 2)$

2. Solve the two equations for k

7 additional steps

$(4 k + 5) = (3 k - 2)$

Subtract from both sides:

$(4 k + 5) - 3 k = (3 k - 2) - 3 k$

Group like terms:

$(4 k - 3 k) + 5 = (3 k - 2) - 3 k$

Simplify the arithmetic:

$k + 5 = (3 k - 2) - 3 k$

Group like terms:

$k + 5 = (3 k - 3 k) - 2$

Simplify the arithmetic:

$k + 5 = - 2$

Subtract from both sides:

$(k + 5) - 5 = - 2 - 5$

Simplify the arithmetic:

$k = - 2 - 5$

Simplify the arithmetic:

$k = - 7$

10 additional steps

$(4 k + 5) = - (3 k - 2)$

Expand the parentheses:

$(4 k + 5) = - 3 k + 2$

Add to both sides:

$(4 k + 5) + 3 k = (- 3 k + 2) + 3 k$

Group like terms:

$(4 k + 3 k) + 5 = (- 3 k + 2) + 3 k$

Simplify the arithmetic:

$7 k + 5 = (- 3 k + 2) + 3 k$

Group like terms:

$7 k + 5 = (- 3 k + 3 k) + 2$

Simplify the arithmetic:

$7 k + 5 = 2$

Subtract from both sides:

$(7 k + 5) - 5 = 2 - 5$

Simplify the arithmetic:

$7 k = 2 - 5$

Simplify the arithmetic:

$7 k = - 3$

Divide both sides by :

$\frac{(7 k)}{7} = \frac{- 3}{7}$

Simplify the fraction:

$k = \frac{- 3}{7}$

3. List the solutions

$k = - 7, - \frac{3}{7}$
(2 solution(s))

4. Graph

Each line represents the function of one side of the equation:
$y = | 4 k + 5 |$
$y = | 3 k - 2 |$
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 k

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 k

3. List the solutions

4. Graph

Why learn this

Terms and topics

Related links

Latest Related Drills Solved