Enter an equation or problem
Camera input is not recognized!

Solution - Absolute value equations

Exact form: x=-4,-12
x=-4 , -\frac{1}{2}
Decimal form: x=4,0.5
x=-4 , -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
|3x2|=|5x+6|
without the absolute value bars:

|x|=|y||3x2|=|5x+6|
x=+y(3x2)=(5x+6)
x=y(3x2)=(5x+6)
+x=y(3x2)=(5x+6)
x=y(3x2)=(5x+6)

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||3x2|=|5x+6|
x=+y , +x=y(3x2)=(5x+6)
x=y , x=y(3x2)=(5x+6)

2. Solve the two equations for x

13 additional steps

(3x-2)=(5x+6)

Subtract from both sides:

(3x-2)-5x=(5x+6)-5x

Group like terms:

(3x-5x)-2=(5x+6)-5x

Simplify the arithmetic:

-2x-2=(5x+6)-5x

Group like terms:

-2x-2=(5x-5x)+6

Simplify the arithmetic:

2x2=6

Add to both sides:

(-2x-2)+2=6+2

Simplify the arithmetic:

2x=6+2

Simplify the arithmetic:

2x=8

Divide both sides by :

(-2x)-2=8-2

Cancel out the negatives:

2x2=8-2

Simplify the fraction:

x=8-2

Move the negative sign from the denominator to the numerator:

x=-82

Find the greatest common factor of the numerator and denominator:

x=(-4·2)(1·2)

Factor out and cancel the greatest common factor:

x=4

12 additional steps

(3x-2)=-(5x+6)

Expand the parentheses:

(3x-2)=-5x-6

Add to both sides:

(3x-2)+5x=(-5x-6)+5x

Group like terms:

(3x+5x)-2=(-5x-6)+5x

Simplify the arithmetic:

8x-2=(-5x-6)+5x

Group like terms:

8x-2=(-5x+5x)-6

Simplify the arithmetic:

8x2=6

Add to both sides:

(8x-2)+2=-6+2

Simplify the arithmetic:

8x=6+2

Simplify the arithmetic:

8x=4

Divide both sides by :

(8x)8=-48

Simplify the fraction:

x=-48

Find the greatest common factor of the numerator and denominator:

x=(-1·4)(2·4)

Factor out and cancel the greatest common factor:

x=-12

3. List the solutions

x=-4,-12
(2 solution(s))

4. Graph

Each line represents the function of one side of the equation:
y=|3x2|
y=|5x+6|
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.