16Hit1600
Advanced MathEasy–MediumFactor of a difference of squares

Advanced Math practice question

The expression x² − 16 can be written as (x + 4)(x − k), where k is a positive constant. What is the value of k?

Answer: 4

x² − 16 = (x + 4)(x − 4).

Common wrong answers

If you answered 8
8 is 16 ÷ 2.
If you answered 16
16 is the constant term, not its square root.
If you answered -4
The question asks for the positive constant k in (x − k).

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