SOLUTION: Solve the equation. Check for extraneous solutions. |4x|=28 I dont understand how to do extraneous solutions |4x|=28 28 divided by 4 is 7 so x=7 But how do i check fo

Algebra ->  Absolute-value -> SOLUTION: Solve the equation. Check for extraneous solutions. |4x|=28 I dont understand how to do extraneous solutions |4x|=28 28 divided by 4 is 7 so x=7 But how do i check fo      Log On


   



Question 816102: Solve the equation. Check for extraneous solutions.
|4x|=28
I dont understand how to do extraneous solutions
|4x|=28 28 divided by 4 is 7 so x=7
But how do i check for extraneous solutions?

Answer by algebrahouse.com(1659) About Me  (Show Source):
You can put this solution on YOUR website!
Absolute value is the distance away from zero.
|4x| = 28
4x = 28 or 4x = -28 {the two numbers that are 28 away from zero are 28 and -28}
x = 7 or x = -7 {divided each side by 4}

Check. If it makes a false statement, then it is an extraneous solution.

Check 7:
|4(7)| = 28
|28| = 28 {multiplied}
28 = 28 {true statement, so 7 is not extraneous}

Check -7:
|4(-7)| = 28
|-28| = 28 {multiplied}
28 = 28 {a true statement, so -7 is not extraneous}

For more help from me, visit: www.algebrahouse.com