Question

Nigel makes the claim that x=6 is the solution to the equation 4(5x−12)−7x=5x. His work to support his claim follows. Given: 4(5x−12)−7x=5x Step 1: 20x−48−7x=5x Step 2: 20x−7x−48=5x Step 3: 13x−48=5x Step 4: 13x−13x−48=5x−13x Step 5: 0−48=−8x Step 6: 6=x Which of the following justifications can be used to justify and support Nigel's work? Select all justifications that are correct.

Step 1 is justified by the Distributive Property. , Step 1 is justified by the Distributive Property. , ,

Step 4 is justified by the Symmetric Property. , Step 4 is justified by the Symmetric Property. , ,

Step 5 is justified by the Property of Additive Inverses. , Step 5 is justified by the Property of Additive Inverses. , ,

Step 2 is justified by the Commutative Property. , Step 2 is justified by the Commutative Property. , ,

Step 6 is justified by the Associative Property.

Answer 1

Step 1 is justified by the Distributive Property.

Step 4 is justified by the Symmetric Property

Explanation:

Given the equation solved by Nigel expressed as

4(5x−12)−7x=5x.

First, we need to expand the bracket using the distributive property

4(5x−12)−7x=5x.

4(5x)-4(12) -7x = 5x

20x - 48 - 7x = 5x

Hence Step 1 is justified by the Distributive Property.

Next is to collect the like terms;

20x - 7x - 48 = 5x

Take the difference

13x - 48 = 5x

Next is to subtract 13x from both sides according to the symmetric property

13x - 48 - 13x = 5x - 13x

Hence Step 4 is justified by the Symmetric Property

The resulting equation will be

0-48 = -8x

Divide both sides by -8

-48/-8 = -8x/-8

6 = x

Hence the correct justifications are Step 1 is justified by the Distributive Property AND Step 4 is justified by the Symmetric Property