Advanced MathHardConstant from cancelling a difference of squares
Advanced Math practice question
For x ≠ −3/2, (4x² − 9)/(2x + 3) is equivalent to 2x − c, where c is a constant. What is the value of c?
Answer: 3
4x² − 9 = (2x − 3)(2x + 3). Dividing by (2x + 3) leaves 2x − 3, so c = 3.
Common wrong answers
- If you answered 9
- 9 is the constant in the original numerator before factoring.
- If you answered -3
- −3 would give 2x + 3, the factor that was cancelled.
- If you answered 1.5
- 1.5 is 3/2, the excluded value's size, not c.
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