Question 8

Kelsey solved the following equation:

[tex]\[ 7x - \frac{1}{2}(8x + 2) = 6 \][/tex]

| Step | Work | Justification |
|------|----------------|----------------|
| 1 | [tex]\( 7x - 4x - 1 = 6 \)[/tex] | |
| 2 | [tex]\( 3x - 1 = 6 \)[/tex] | |
| 3 | [tex]\( 3x = 7 \)[/tex] | |
| 4 | [tex]\( x = \frac{7}{3} \)[/tex] | |

Which of the following lists all of the correct justifications Kelsey used to solve this equation?

A. 1. Distributive property 2. Combine like terms 3. Addition property of equality 4. Division property of equality

B. 1. Multiplication property of equality 2. Combine like terms 3. Addition property of equality 4. Division property of equality

C. 1. Distributive property 2. Combine like terms 3. Subtraction property of equality 4. Division property of equality

D. 1. Multiplication property of equality 2. Combine like terms 3. Subtraction property of equality 4. Division property of equality



Answer :

Let's go through the steps Kelsey used to solve the equation [tex]\(7x - \frac{1}{2}(8x + 2) = 6\)[/tex] and understand the justifications for each step:

1. The initial equation is:
[tex]\[ 7x - \frac{1}{2}(8x + 2) = 6 \][/tex]

2. Step 1: Distribute [tex]\(\frac{1}{2}\)[/tex] to both terms inside the parentheses:
[tex]\[ 7x - 4x - 1 = 6 \][/tex]
- Justification: Distributive property. This property allows us to distribute a factor (in this case, [tex]\(\frac{1}{2}\)[/tex]) to both terms inside the parentheses.

3. Step 2: Combine like terms on the left side of the equation:
[tex]\[ 3x - 1 = 6 \][/tex]
- Justification: Combine like terms. We combine [tex]\(7x\)[/tex] and [tex]\(-4x\)[/tex] to get [tex]\(3x\)[/tex].

4. Step 3: Add 1 to both sides to isolate the term with [tex]\(x\)[/tex]:
[tex]\[ 3x = 7 \][/tex]
- Justification: Addition property of equality. This property allows us to add the same number (in this case, adding 1) to both sides of the equation.

5. Step 4: Divide both sides by 3 to solve for [tex]\(x\)[/tex]:
[tex]\[ x = \frac{7}{3} \][/tex]
- Justification: Division property of equality. This property allows us to divide both sides of the equation by the same nonzero number (in this case, 3).

Putting it all together:
1. Distributive property
2. Combine like terms
3. Addition property of equality
4. Division property of equality

So, the correct sequence of justifications Kelsey used to solve this equation is:
Distributive property, Combine like terms, Addition property of equality, Division property of equality.

The correct answer is:
1. Distributive property 2 Combine like terms 3 Addition property of equality 4 Division property of equality