Jakob simplified the expression as shown. \[ \begin{array}{l} (6.7 x-3)-(3.4 x-1)-(2 x-2) \\ 6.7 x-3-3.4 x-1-2 x-2 \\ (6.7 x-3.4 x-2 x)+(-3-1-2) \\ 1.3 x-6 \end{array} \] What was Jakob's error in subtracting the expressions? He used the commutative property incorrectly. He used the distributive property incorrectly. He used the associative property incorrectly. He simplified the \( x \) coefficients incorrectly.

To identify Jakob's error in simplifying the expression, let's analyze each step he took: 1. **Original Expression:** \[ (6.7 x - 3) - (3.4 x - 1) - (2 x - 2) \] 2. **First Step:** \[ 6.7 x - 3 - 3.4 x + 1 - 2 x + 2 \] Here, Jakob correctly distributed the negative signs across the terms in the parentheses. 3. **Second Step:** \[ (6.7 x - 3.4 x - 2 x) + (-3 + 1 + 2) \] This step is also correct as he grouped the \( x \) terms and the constant terms separately. 4. **Final Step:** \[ 1.3 x - 6 \] Here, Jakob made an error in simplifying the constant terms. The correct simplification of the constants should be: \[ -3 + 1 + 2 = 0 \] Therefore, the final expression should be: \[ 1.3 x + 0 = 1.3 x \] Jakob's error was in simplifying the \( x \) coefficients incorrectly, as he did not correctly calculate the sum of the constant terms. Thus, the correct answer is: **He simplified the \( x \) coefficients incorrectly.**