How do you solve and check for extraneous solutions in abs(5-4w)= 3w?

1 Answer
Aug 1, 2015

color(red)(w = 5/7) and color(red)(w = 5) are solutions.
There are color(red)("no") extraneous solutions.

SOLVE

|5-4w| = 3w

We need to write two different equations without the absolute value symbols and solve for w.

These equations are:

(1): (5-4w) = 3w
(2): -(5-4w) = 2w

Solve Equation 1:

5-4w = 3w

Add 4w to each side.

5 = 7w

Divide each side by 7.

w = 5/7

Solve Equation 2:

−(5-4w) = 3w

Remove parentheses.

-5+4w= 3w

Subtract 3w from each side.

-5+w = 0

Add 5 to each side..

w = 5

The solutions are w = 5/7 and w = 5.

CHECK FOR EXTRANEOUS SOLUTIONS:

If w=5/7,

|5-4w|=3w

|5-4(5/7)|= 3(5/7)

|5-20/7| = 15/7

|(35-20)/7| =15/7

|15/7| = 15/7

15/7=15/7

w = 5/7 is a solution.

If w=5,

|5-4w| = 3w
|5-4(5)| = 3(5)
|5-20| = 15
|15| = 15
15 = 15

w=5 is a solution.

There are no extraneous solutions.