Advanced MathHardConstant in a factored form
Advanced Math practice question
For all x, 3x(x − 4) + 2(x − 4) = (3x + k)(x − 4), where k is a constant. What is the value of k?
Answer: 2
Both terms share (x − 4): (x − 4)(3x + 2). So k = 2.
Common wrong answers
- If you answered 6
- 6 comes from multiplying 3 by 2, but k is just the coefficient of the second term.
- If you answered -4
- −4 is the constant in the OTHER factor, (x − 4).
- If you answered -2
- −2 has the wrong sign; the shared factor leaves +2.
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