Advanced MathHardLinear form of a difference of a square and a monomial
Advanced Math practice question
The expression 3(x − 4)² − 3x² can be rewritten in the form ax + b, where a and b are constants. What is the value of a?
Answer: -24
3(x² − 8x + 16) − 3x² = 3x² − 24x + 48 − 3x² = −24x + 48. So a = −24.
Common wrong answers
- If you answered 24
- 24 has the wrong sign: the −8x term is multiplied by +3.
- If you answered 48
- 48 is b, not a.
- If you answered -12
- −12 comes from 3 × (−4), not doubling the middle term of the square.
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