The table shows the solution to the equation |2x - 4| - 3 = 3:

Question

Which is the first incorrect step?

Step 1

Step 2

Step 3

Solution is correct

Answer 1

First:  Note that |2x - 4| - 3 = 3

 

What needs to be done to isolate the variable?  

 

Add 3

 

That gives:  |2x - 4| = 6.

 

There are two answers at this point:  +6 and -6.

 

Therefore:  2x - 4 = 6,   2x = 10,   x = 5.

 

        and:   2x - 4 = -6,  2x = -2,   x = -1.

 

But wait ..... were are not done:  Check:  |2(5)-4| -3 = |10-4| -3 = 6-3 =3,  |2(-1)-4| = |-2-4|-3 = 6-3 = 3.

 

I hope this explains the problem.  Remember, each absolute value problem has two answers, at most .