Final answer:
Without specific details of the inequality and Stacy's solution steps, it's impossible to identify her first mistake in solving the inequality. Common errors include incorrect manipulation of inequality signs and arithmetic mistakes.
Step-by-step explanation:
The student's question relates to identifying the first mistake made by Stacy when solving an inequality. Since the inequality and the steps taken by Stacy to solve it are not provided, we cannot determine where the mistake occurred. However, common mistakes when solving inequalities include incorrect manipulation of the inequality sign (such as forgetting to reverse it when multiplying or dividing by a negative number), improper distribution of terms, and addition or subtraction errors. To properly identify the mistake, each step must be analyzed to ensure that arithmetic operations are performed correctly, that the inequality is manipulated according to mathematical rules, and that all terms are accounted for. A detailed step-by-step explanation would be necessary to pinpoint the error Stacy might have made.