Advanced MathMediumConstant in a grouped factorisation
Advanced Math practice question
For all x, 4x(x − 1) + 3(x − 1) = (x − 1)(4x + k). What is the value of k?
Answer: 3
Both terms share (x − 1): (x − 1)(4x + 3). So k = 3.
Common wrong answers
- If you answered 12
- 12 multiplies 4 by 3.
- If you answered -3
- −3 would give 4x − 3, the wrong sign.
- If you answered -1
- −1 is the constant in the shared factor.
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