Q. Which expression is equivalent to −381−221 ?Choose 1 answer:(A) 381−221(B) 221−381(C) 221−(−381)(D) −381+(−221)
Understand the problem: Understand the problem.We need to find the expression that is equivalent to the given expression −3(81)−2(21).
Analyze the answer choices: Analyze the answer choices.(A) 3(81)−2(21) changes the sign of the first term.(B) 2(21)−3(81) changes the order and the signs of the terms.(C) 2(21)−(−3(81)) changes the order of the terms and adds a negative sign in front of the second term.(D) −3(81)+(−2(21)) keeps the first term the same and adds a negative sign in front of the second term.
Compare with original expression: Compare the original expression with the answer choices.The original expression is −3(81)−2(21). We need to find an equivalent expression, which means the mathematical value should remain unchanged.
Evaluate each answer choice: Evaluate each answer choice.(A) 3(81)−2(21) is not equivalent because the sign of the first term is different from the original expression.(B) 2(21)−3(81) is not equivalent because the order of the terms is reversed, which changes the subtraction to addition for the first term.(C) 2(21)−(−3(81)) is not equivalent because the order of the terms is reversed, and the negative sign in front of the second term changes the operation from subtraction to addition.(D) −3(81)+(−2(21)) is equivalent because it keeps the first term the same and the addition of a negative is the same as subtraction, so the mathematical value is unchanged.
Choose the correct answer: Choose the correct answer.The correct answer is (D) −3(81)+(−2(21)) because it is the only choice that maintains the mathematical value of the original expression.
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