SOLUTION: |4x+4|=8x+16

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Question 491119: |4x+4|=8x+16
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
|4x+4| = 8x+16

The absolute value is already isolated so we can split into two
equations without absolute value bars:

1. One equation is when what is between the absolute value bars equals
to the right side:

 4x+4 = 8x+16
4x-8x = 16-4
  -4x = 12
    x = 12%2F%28-4%29
    x = -3  

But we must check for extraneous solutions:

   |4x+4| = 8x+16
|4(-3)+4| = 8(-3)+16
   |12+4| = -24+1
     |16| = -23
       16 = -23

That is false so -3 is extraneous, and is tot a solution

2. Another equation is when what is between the absolute value bars equals
to -1 times the right side:

4x+4 = -1(8x+16)
4x+4 = -8x-16
 12x = -20
   x = %28-20%29%2F12
   x = -5%2F3

Checking for extraneous solutions:

  |4x+4| = 8x+16
|4(-5%2F3+4| = 8(-5%2F3)+16
|-20%2F3+12%2F3| = -40%2F3+48%2F3
    |-8%2F3| = 8%2F3  
       8%2F3 = 8%2F3
That's true so there is just one solution, -5%2F3


Edwin