9514 1404 393
Answer:
x = -6 (correct answer)
mistakes were made in Step 2 and Step 5.
Step-by-step explanation:
The mistake is made in Step 2, application of the distributive property. This is often a source of error. Here, the error is in signs.
Step 1: 12 = -2(x -4) -8
Step 2: 12 = -2x +8 -8 . . . . . . the correct step 2
Step 3: 12 = -2x . . . . . . . . . . . like terms combined
Step 4: -6 = x . . . . . . . . . . . . . divide by -2
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<em>Check</em>
12 = -2(-6 -4) -8 = -2(-10) -8 = 20 -8 = 12 . . . . answer checks OK
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<em>Comment on other mistake</em>
In the original Step 5, -2 was divided on the right and added on the left. This is a violation of the properties of equality, so guarantees a wrong answer. The same operation must be performed on both sides of the equation.
An additional mistake was made in that the answer was not checked.
