Advanced MathEasyPositive root of a factored quadratic
Advanced Math practice question
For what positive value of x is (x − 4)(x + 2) equal to 0?
Answer: 4
A product is 0 when a factor is 0: x − 4 = 0 gives x = 4 (x + 2 = 0 gives −2, which is not positive).
Common wrong answers
- If you answered 2
- 2 gives (−2)(4) = −8.
- If you answered 8
- 8 gives (4)(10) = 40.
- If you answered -2
- −2 makes the second factor zero but is not positive.
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