Jen solved the equation [tex]\(100 - \frac{1}{2} x = 92\)[/tex] to determine the number of questions, [tex]\(x\)[/tex], she answered incorrectly on a test. She began by subtracting 100 from both sides, then multiplying both sides by -2. Which best describes the accuracy of Jen's work?

A. Incorrect. She needed to add 100 to both sides instead of subtracting 100.
B. Incorrect. She needed to multiply both sides by -2 first, then subtract 100.
C. Correct. She could have also subtracted 100 from both sides, then divided by [tex]\(-\frac{1}{2}\)[/tex].
D. Correct. She could have also multiplied both sides by -2 first, then subtracted 100.



Answer :

Let's carefully analyze the steps that Jen took to solve the equation [tex]\(100 - \frac{1}{2}x = 92\)[/tex].

### Step-by-step analysis:

1. Initial Equation:
[tex]\[ 100 - \frac{1}{2}x = 92 \][/tex]

2. Jen's first step: Subtract 100 from both sides
[tex]\[ 100 - \frac{1}{2}x - 100 = 92 - 100 \][/tex]
Simplifies to:
[tex]\[ -\frac{1}{2}x = -8 \][/tex]

3. Jen's second step: Multiply both sides by -2
[tex]\[ -2 \cdot \left(-\frac{1}{2}x\right) = -2 \cdot (-8) \][/tex]
Simplifies to:
[tex]\[ x = 16 \][/tex]

By following the steps, Jen correctly determined that [tex]\( x = 16 \)[/tex]. Now, we need to evaluate the descriptions of Jen's work:

### Description:
1. "Incorrect. She needed to add 100 to both sides instead of subtracting 100."

This statement is incorrect. Subtracting 100 from both sides is a valid step in solving this type of equation.

2. "Incorrect. She needed to multiply both sides by -2 first, then subtract 100."

This statement is also incorrect. It is not necessary to multiply both sides by -2 first; subtracting 100 initially is a valid approach.

3. "Correct. She could have also subtracted 100 from both sides, then divided by [tex]\(-\frac{1}{2}\)[/tex]."

This statement is correct. Another approach could have been to first subtract 100 from both sides and then deal with the coefficient of [tex]\(x\)[/tex] by dividing by [tex]\(-\frac{1}{2}\)[/tex].

4. "Correct. She could have also multiplied both sides by -2 first, then subtracted 100."

This statement is correct as well. Jen could have first multiplied both sides by -2 and then addressed the resulting equation.

### Conclusion:
Based on the analysis, the best descriptions of Jen's work are the third and fourth options:

- Correct. She could have also subtracted 100 from both sides, then divided by [tex]\(-\frac{1}{2}\)[/tex].
- Correct. She could have also multiplied both sides by -2 first, then subtracted 100.

Hence, the correct responses are options 3 and 4.