Final answer:
The error made by Jack is failure to simplify terms. When evaluating an expression, it is important to simplify the terms before doing any calculations. The correct answer is b) Failure to simplify terms.
Step-by-step explanation:
The error made by Jack is failure to simplify terms.
When evaluating an expression, it is important to simplify the terms before doing any calculations. This involves combining like terms and reducing the expression to its simplest form. By not simplifying the terms, Jack might have ended up with a more complex expression that could lead to incorrect results.
For example, if the original expression was 2x + 3x, Jack should have combined the x terms to get 5x before continuing with the evaluation.
Therefore, the correct answer is b) Failure to simplify terms.