Advanced MathHardCommon factor of a difference
Advanced Math practice question
For all values of x, (3x)² − 9 = k(x² − 1), where k is a constant. What is the value of k?
Answer: 9
(3x)² − 9 = 9x² − 9 = 9(x² − 1).
Common wrong answers
- If you answered 3
- 3 forgets to square the 3.
- If you answered 6
- 6 doubles 3.
- If you answered -9
- −9 has the sign wrong.
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