Enter an equation or problem
Camera input is not recognized!

Solution - Absolute value equations

Exact form: n=7,3
n=7 , -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
|n+8|=|2n+1|
without the absolute value bars:

|x|=|y||n+8|=|2n+1|
x=+y(n+8)=(2n+1)
x=y(n+8)=(2n+1)
+x=y(n+8)=(2n+1)
x=y(n+8)=(2n+1)

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||n+8|=|2n+1|
x=+y , +x=y(n+8)=(2n+1)
x=y , x=y(n+8)=(2n+1)

2. Solve the two equations for n

10 additional steps

(n+8)=(2n+1)

Subtract from both sides:

(n+8)-2n=(2n+1)-2n

Group like terms:

(n-2n)+8=(2n+1)-2n

Simplify the arithmetic:

-n+8=(2n+1)-2n

Group like terms:

-n+8=(2n-2n)+1

Simplify the arithmetic:

n+8=1

Subtract from both sides:

(-n+8)-8=1-8

Simplify the arithmetic:

n=18

Simplify the arithmetic:

n=7

Multiply both sides by :

-n·-1=-7·-1

Remove the one(s):

n=-7·-1

Simplify the arithmetic:

n=7

12 additional steps

(n+8)=-(2n+1)

Expand the parentheses:

(n+8)=-2n-1

Add to both sides:

(n+8)+2n=(-2n-1)+2n

Group like terms:

(n+2n)+8=(-2n-1)+2n

Simplify the arithmetic:

3n+8=(-2n-1)+2n

Group like terms:

3n+8=(-2n+2n)-1

Simplify the arithmetic:

3n+8=1

Subtract from both sides:

(3n+8)-8=-1-8

Simplify the arithmetic:

3n=18

Simplify the arithmetic:

3n=9

Divide both sides by :

(3n)3=-93

Simplify the fraction:

n=-93

Find the greatest common factor of the numerator and denominator:

n=(-3·3)(1·3)

Factor out and cancel the greatest common factor:

n=3

3. List the solutions

n=7,3
(2 solution(s))

4. Graph

Each line represents the function of one side of the equation:
y=|n+8|
y=|2n+1|
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.