Question

Jamar's teacher told him that one of the reasons he gave on the proof below was incorrect. Which reason did he make the mistake on? Tell me the number of the reason he got wrong and which property he should have used instead (use your blue foldable, if needed).

Statements

1. 2(3x + 4) = 56
Reasons

1. Given

2. 6x + 8 = 56
2. Multiplication Property of Equality
3. 6x + 8 - 8 = 56 - 8
3. Subtraction Property of Equality
4. 6x = 48 4. Simplify

5. 6x6=486 5. Division Property of Equality
6. x = 8
6. Simplify

Answer 1

Reason given in step 2. is incorrect. It should read; "Distributive Property."

Explanation:

The reason given to go from :

2 (3x +4) = 56 to 6x + 8 = 56

is NOT "Multiplication Property of Equality" because one is not multiplying both sides of the equality by a number. The property that is being used is the Distributive Property on the left side of the equation in order to remove the grouping symbols (parenthesis) performing the implied multiplication of the external factor times each term of the binomial in parenthesis.