Question
Rafael writes an expression to represent “a number, n, decreased by thirty-one.” Then he evaluates that expression if n = 29. Which statements are true about the expression and its evaluation? Check all that apply.
The correct expression is 31 minus n.
This is a subtraction expression.
This is an addition expression.
To evaluate, substitute 29 for the variable in the expression.
To evaluate, substitute 31 for the variable in the equation.
To evaluate the expression, add 31 to 29.
The correct expression is n minus 31.
To evaluate the expression, subtract 31 from 29.
The correct expression is 31 minus n.
This is a subtraction expression.
This is an addition expression.
To evaluate, substitute 29 for the variable in the expression.
To evaluate, substitute 31 for the variable in the equation.
To evaluate the expression, add 31 to 29.
The correct expression is n minus 31.
To evaluate the expression, subtract 31 from 29.
Answers
Answered by
GPT-4o mini
Let's analyze the problem step by step:
1. **Understanding the expression**: The phrase "a number, n, decreased by thirty-one" can be correctly represented by the expression \( n - 31 \).
2. **Evaluating the expression**: If we substitute \( n = 29 \) into the expression \( n - 31 \), we get:
\[
29 - 31 = -2
\]
Now, let's evaluate the statements one by one:
1. **The correct expression is 31 minus n.**
- **False** (The correct expression is \( n - 31 \).)
2. **This is a subtraction expression.**
- **True** (The expression involves subtraction.)
3. **This is an addition expression.**
- **False** (The expression involves subtraction, not addition.)
4. **To evaluate, substitute 29 for the variable in the expression.**
- **True** (To evaluate the expression \( n - 31 \), we substitute \( n \) with 29.)
5. **To evaluate, substitute 31 for the variable in the equation.**
- **False** (We substitute 29 for \( n \), not 31.)
6. **To evaluate the expression, add 31 to 29.**
- **False** (We subtract 31 from 29, not add.)
7. **The correct expression is n minus 31.**
- **True** (This accurately reflects “a number, n, decreased by thirty-one.”)
8. **To evaluate the expression, subtract 31 from 29.**
- **True** (We subtract 31 from 29 to evaluate the expression.)
Based on this analysis, the true statements are:
- This is a subtraction expression.
- To evaluate, substitute 29 for the variable in the expression.
- The correct expression is n minus 31.
- To evaluate the expression, subtract 31 from 29.
1. **Understanding the expression**: The phrase "a number, n, decreased by thirty-one" can be correctly represented by the expression \( n - 31 \).
2. **Evaluating the expression**: If we substitute \( n = 29 \) into the expression \( n - 31 \), we get:
\[
29 - 31 = -2
\]
Now, let's evaluate the statements one by one:
1. **The correct expression is 31 minus n.**
- **False** (The correct expression is \( n - 31 \).)
2. **This is a subtraction expression.**
- **True** (The expression involves subtraction.)
3. **This is an addition expression.**
- **False** (The expression involves subtraction, not addition.)
4. **To evaluate, substitute 29 for the variable in the expression.**
- **True** (To evaluate the expression \( n - 31 \), we substitute \( n \) with 29.)
5. **To evaluate, substitute 31 for the variable in the equation.**
- **False** (We substitute 29 for \( n \), not 31.)
6. **To evaluate the expression, add 31 to 29.**
- **False** (We subtract 31 from 29, not add.)
7. **The correct expression is n minus 31.**
- **True** (This accurately reflects “a number, n, decreased by thirty-one.”)
8. **To evaluate the expression, subtract 31 from 29.**
- **True** (We subtract 31 from 29 to evaluate the expression.)
Based on this analysis, the true statements are:
- This is a subtraction expression.
- To evaluate, substitute 29 for the variable in the expression.
- The correct expression is n minus 31.
- To evaluate the expression, subtract 31 from 29.