Advanced Math practice question

Answer: A. 3(x + 3)(x − 1)

Factor out 3: 3(x² + 2x − 3). Then x² + 2x − 3 = (x + 3)(x − 1). Check: (x + 3)(x − 1) = x² + 2x − 3.

Why the other answers are wrong

B. 3(x − 3)(x + 1)

(x − 3)(x + 1) = x² − 2x − 3, the wrong middle sign.

C. (3x + 3)(x − 3)

(3x + 3)(x − 3) = 3x² − 6x − 9, the wrong middle sign.

D. 3(x + 3)(x + 1)

(x + 3)(x + 1) = x² + 4x + 3, wrong middle term and constant.

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