Question 1
A) Incorrect Work by Classmates
Joey: \[ (2x)(x) + (2x)(12) + (-5)(x) + (-5)(12) \Rightarrow 2x^2 + 24x - 5x - 60 \] Final result: \(2x^2 + 19x - 60\)
Erin: Correctly calculated individual products: \[ (2x)(x) = 2x^2 \] \[ (2x)(12) = 24x \] \[ (-5)(x) = -5x \] \[ (-5)(12) = -60 \] Final result: \(2x^2 + 19x - 60\)
Incorrect Classmate
Both classmates initially followed the process correctly but made a mistake in simplification. Joey simplified \(24x - 5x\) to \(19x\), which is correct, but didn't show the intermediate steps clearly. Erin made no apparent mistakes in the calculations.
Conclusion: Erin completed the problem correctly, while Joey followed the process correctly but did not emphasize clarity in combining like terms. Erin's presentation and clarity in showing steps made it easier to follow.
Question 2
A) Cost Modeling Expressed
Matt's total cost, including the one-time meeting fee and the cost per walk, can be modeled as: \[ C = 10 + 14w \] Where \(C\) is total cost and \(w\) is the number of walks.
Total Cost for 6 Walks
Total cost for 6 walks: \[ C = 10 + 14(6) \] Calculating: \[ C = 10 + 84 = 94 \] Thus, the total cost for 6 walks is $94.
Question 3
A) First Step in Simplification
To simplify the expression \((2x^3 - 12x^2 + 5x - 3) - (7x^3 + 10x^2 - 3x + 20)\), the first step is: Distribute the negative to the second set of parentheses.
Question 4
A) Simplification Fill-in
Expression: \[ (6x^3 + 2x^2 - 5x - 14) - (-5x^3 + 7x^2 + 2x - 1) \]
After distributing the negative, it becomes: \[ 6x^3 + 2x^2 - 5x - 14 + 5x^3 - 7x^2 - 2x + 1 \]
Fill in the blanks showing signs: 6x³, +, 2x², -, 5x, -, 14, +, 5x³, -, 7x², -, 2x, +, 1
Question 5
A) Length of the Missing Side
Given perimeter: \[ 21x^2 - 5x + 4 \] Let \(S\) be the total length of the sides that are known. If you know that: \[ P = S + \text{(missing side)} \] The missing side can be found by subtracting the known perimeter from \(P\).
Assuming known sides are \(S\), then the length of missing side would be expressed as: \[ \text{missing side} = 21x^2 - 5x + 4 - S \]
Exact length can’t be determined without knowing \(S\) or the lengths of other sides.
Question 6
A) Correct Distribution
For the expression \((2x + 3)(3x - 1)\), the correct and complete distribution should include all terms: \[ 2x \cdot 3x + 2x \cdot -1 + 3 \cdot 3x + 3 \cdot -1 \]
Correct response: \(2x \cdot 3x + 2x \cdot -1 + 3 \cdot 3x + 3 \cdot -1\)
Question 7
A) Cost Expression
The cost of the app for \(m\) months is expressed as: \[ C = 2 + 5m \]
The correct response: \(2 + 5m = c\)
Question 8
A) Coefficients Identification
For the expression \(3x^2 + 5x - 12\), the coefficients are: 3, 5, -12
Question 9
A) Constant Identification
In the expression \(2x^3 - 8x^2 - 10x + 1\), the constant is: 1
Question 10
A) Expression or Equation Classification
- \(2x^3 - 4x^2\) - Expression
- \(x = 3\) - Equation
- \(5x = 25\) - Equation
- \(3x + 2\pi\) - Expression