Question 374 of 480
Simplify the expression \(3x + 5 - 2x + 7\). What is the simplified form?
- \(x + 12\)
- \(5x + 12\)
- \(x + 2\)
- \(x + 6\)
Correct Answer:
A
Explanation
To simplify the expression \(3x + 5 - 2x + 7\), we will follow a systematic approach. Let's break it down step-by-step.
### Step 1: Identify Like Terms
In the expression \(3x + 5 - 2x + 7\), we can identify two types of terms:
- **Like terms involving \(x\)**: \(3x\) and \(-2x\)
- **Constant terms**: \(5\) and \(7\)
### Step 2: Combine Like Terms
Now, we will combine the like terms.
#### Combining the \(x\) terms:
- Start with \(3x\) and subtract \(2x\):
\[
3x - 2x = (3 - 2)x = 1x = x
\]
#### Combining the constant terms:
- Now, add the constants \(5\) and \(7\):
\[
5 + 7 = 12
\]
### Step 3: Write the Simplified Expression
After combining the like terms, we can write the simplified expression:
\[
x + 12
\]
### Conclusion
The final simplified form of the expression \(3x + 5 - 2x + 7\) is \(x + 12\).
### Answer
The correct option is **A. \(x + 12\)**.
### Explanation of Other Options
Now, let's analyze the other options to understand why they are incorrect:
- **Option B: \(5x + 12\)**
- This option incorrectly suggests that the coefficient of \(x\) is \(5\). However, we found that the coefficient is actually \(1\) after combining \(3x\) and \(-2x\).
- **Option C: \(x + 2\)**
- This option incorrectly states that the constant term is \(2\). We calculated the constant terms to be \(12\), not \(2\).
- **Option D: \(x + 6\)**
- Similar to option C, this option incorrectly states that the constant term is \(6\). Our calculation showed that the correct constant term is \(12\).
### Common Pitfalls
- **Forgetting to combine like terms**: Always ensure you group and combine terms that are similar (i.e., terms with the same variable or constant terms).
- **Miscalculating constants**: Double-check your arithmetic when adding or subtracting constants to avoid errors.
### Revision Summary
- Identify and group like terms in an expression.
- Combine coefficients of \(x\) and constant terms separately.
- Ensure to double-check calculations to avoid simple arithmetic mistakes.
- The simplified form of \(3x + 5 - 2x + 7\) is \(x + 12\).