Enter an equation or problem
Camera input is not recognized!

Solution - Absolute value equations

Exact form: x=-37,-3
x=-\frac{3}{7} , -3
Decimal form: x=0.429,3
x=-0.429 , -3

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
|7x3|=|7x+3|
without the absolute value bars:

|x|=|y||7x3|=|7x+3|
x=+y(7x3)=(7x+3)
x=y(7x3)=(7x+3)
+x=y(7x3)=(7x+3)
x=y(7x3)=(7x+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||7x3|=|7x+3|
x=+y , +x=y(7x3)=(7x+3)
x=y , x=y(7x3)=(7x+3)

2. Solve the two equations for x

13 additional steps

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

Subtract from both sides:

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

Group like terms:

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

Simplify the arithmetic:

-14x-3=(7x+3)-7x

Group like terms:

-14x-3=(7x-7x)+3

Simplify the arithmetic:

14x3=3

Add to both sides:

(-14x-3)+3=3+3

Simplify the arithmetic:

14x=3+3

Simplify the arithmetic:

14x=6

Divide both sides by :

(-14x)-14=6-14

Cancel out the negatives:

14x14=6-14

Simplify the fraction:

x=6-14

Move the negative sign from the denominator to the numerator:

x=-614

Find the greatest common factor of the numerator and denominator:

x=(-3·2)(7·2)

Factor out and cancel the greatest common factor:

x=-37

5 additional steps

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

Expand the parentheses:

(-7x-3)=-7x-3

Add to both sides:

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

Group like terms:

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

Simplify the arithmetic:

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

Group like terms:

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

Simplify the arithmetic:

3=3

3. List the solutions

x=-37,-3
(2 solution(s))

4. Graph

Each line represents the function of one side of the equation:
y=|7x3|
y=|7x+3|
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.