maria said the expression $-5n + 4 + 7n - 8$ is equivalent to $-2n$. what error did maria likely make?

what error did maria likely make?

a. she multiplied all the numbers instead of adding or subtracting.
b. she did not group like terms correctly. she combined only the first two numbers.
c. she combined only the coefficients of $n$.
d. she did not group like terms correctly. she combined all of the numbers in the expression even though they are not all coefficients of $n$.

Question

maria said the expression $-5n + 4 + 7n - 8$ is equivalent to $-2n$. what error did maria likely make?

what error did maria likely make?

a. she multiplied all the numbers instead of adding or subtracting.
b. she did not group like terms correctly. she combined only the first two numbers.
c. she combined only the coefficients of $n$.
d. she did not group like terms correctly. she combined all of the numbers in the expression even though they are not all coefficients of $n$.

Accepted Answer

{ "quality": "clear", "question_count": 1, "skills_matched": [ "step_cot", "multiple_choice_formatter", "explain_then_answer", "quick" ], "needs_drawing": false, "concepts_used": [ "Equivalent Expressions" ], "new_concepts": [ "Combining Like Terms Error Analysis" ], "current_concepts": [ "Equivalent Expressions", "Combining Like Terms Error Analysis" ] } ## Simplify the original expression correctly $$ \begin{aligned} -5n + 4 + 7n - 8 &= (-5n + 7n) + (4 - 8) \ &= 2n - 4 \end{aligned} $$ ## Analyze Maria's incorrect result $$ \begin{aligned} \text{Maria's result} &= -2n \ \text{Sum of all coefficients and constants} &= -5 + 4 + 7 - 8 \ &= -1 + 7 - 8 \ &= 6 - 8 \ &= -2 \end{aligned} $$ ## Identify the error matching the options $$ \begin{aligned} -5 + 4 + 7 - 8 = -2 \implies \text{Combined all numbers as coefficients of } n \end{aligned} $$

(A) She multiplied all the numbers instead of adding or subtracting.

(B) She did not group like terms correctly. She combined only the first two numbers.

(C) She combined only the coefficients of n.

(D) She did not group like terms correctly. She combined all of the numbers in the expression even though they are not all coefficients of n.

{ "subject": "Mathematics", "question_type": "Multiple Choice", "knowledge_point": [ "Mathematics", "Algebra", "Equivalent Expressions" ] }

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QUESTION IMAGE

Question

Explanation:

Simplify the original expression correctly

Analyze Maria's incorrect result

Identify the error matching the options

Answer: