Advanced Math practice question

Answer: C. x = 4 and x = −4

x² = 16 means x = ±4. Equivalently, factor as (x − 4)(x + 4) = 0. Don't forget the negative root — that's what choice A misses.

Why the other answers are wrong

A. x = 4 only

You found the positive root but dropped the negative one — (−4)² = 16 as well, so x = −4 is also a solution.

B. x = 8 and x = −8

You solved as if the equation were 2x − 16 = 0, halving 16 to get 8. But x² = 16 calls for a square root, not division by 2: x = ±4.

D. x = 16 and x = −16

You moved the 16 across the equal sign but never took the square root. Solving x² = 16 gives x = ±4, and 16² = 256, not 16.

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