Advanced Math practice question

Answer: A. 2x² + 6x

Subtracting a bracket subtracts EVERY term in it: 5x² − 3x² = 2x² and 2x − (−4x) = 2x + 4x = 6x. The result is 2x² + 6x.

Why the other answers are wrong

B. 2x² − 2x

The minus sign was applied to 3x² but not to −4x. Subtracting −4x means ADDING 4x: 2x + 4x = 6x.

C. 8x² − 2x

The x² terms were added instead of subtracted. The bracket is being taken away, so 5x² − 3x² = 2x².

D. 2x² − 6x

2x − 4x = −2x would be right if the second bracket were being added. It's subtracted, which flips −4x to +4x.

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