Advanced Math practice question

Answer: A. x(x − 1)(x + 1)

Factor out x: x(x² − 1). Then x² − 1 is a difference of squares: (x − 1)(x + 1). Result: x(x − 1)(x + 1).

Why the other answers are wrong

B. x(x² + 1)

x(x² + 1) = x³ + x, the wrong sign in the middle.

C. x²(x − 1)

x²(x − 1) = x³ − x², not x³ − x.

D. (x − 1)³

(x − 1)³ expands to x³ − 3x² + 3x − 1.

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