a, |3x + 5| = |x – 7| b, |2x + 2| = |x – 7|

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1. a,$ |3x + 5| = |x – 7| $
   $⇔ 3x + 5 = x – 7 $
   $⇔ 3x – x = -7 – 5 $
   $⇔ 2x = -12$
   $⇔ x = -6$

   b, $|2x + 2| = |x – 7|$
   $⇔ 2x + 2 = x – 7$
   $⇔ 2x – x = -7-2$
   $⇔ x = -9$
   

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2. a, |3x + 5| = |x – 7|

   TH1:

   3x – 5 = x – 7

   2x = -2

   x = -1

   TH2:

   3x – 5 = -(x-7)

   3x – 5 = -x + 7

   4x = 12

   x = 3

   b, |2x + 2| = |x – 7|

   TH1:

   2x + 2 = x – 7

   x = -9

   TH2:

   2x + 2 = -(x-7)

   2x + 2 = -x + 7

   3x = 5

   x = `\frac{5}{3}`

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