Difficulty: Easy
Correct Answer: 240
Explanation:
Introduction / Context:The operator “*” encodes a fixed transformation from two numbers to one number. Find a simple consistent rule that matches all three examples, then apply it to 19 and 11.
Given Data / Assumptions:
Concept / Approach:Test algebraic guesses: a^2 − b^2 works: 9^2 − 7^2 = 81 − 49 = 32; 13^2 − 7^2 = 169 − 49 = 120; 17^2 − 9^2 = 289 − 81 = 208.
Step-by-Step Solution:
Rule: a * b = a^2 − b^2.Apply: 19 * 11 = 19^2 − 11^2 = 361 − 121 = 240.Verification / Alternative check:Confirm the rule fits all provided pairs before applying to the new pair, ensuring consistency.
Why Other Options Are Wrong:They do not match the rule a^2 − b^2 for 19 and 11.
Common Pitfalls:
Final Answer:240
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