Respuesta :

capsasha2

Answer:

The error is that the person divided both sides by positive 4.2 rather than negative 4.2. Here's how to correct it:

  1. -4.2x ÷ -4.2 = x, 21 ÷ -4.2 = -5
  2. So, x = -5.

I hope this helps!

Answer:

He used the commutative property incorrectly.  a

Step-by-step explanation: