If the x-axis intersections of a graph are (-1,0), (3,0), (7,0), what is the mean of their zeroes?
Answer and explanation
Correct answer: 3
Mean \(=\dfrac{-1+3+7}{3}=3\). Explanation: The x-coordinates of the intercepts are the zeros; their sum is 9 and dividing by 3 gives the mean 3. Option 9 is incorrect because it is the sum, not the average (division was omitted). Option -3 results from a sign error, and 7 is just one of the zeros. Exam tip: read off the x-values from intercepts first, then compute average = (sum)/(count).
Frequently asked questions
What is the correct answer to this question?
3
Why is this the correct answer?
Mean \(=\dfrac{-1+3+7}{3}=3\). Explanation: The x-coordinates of the intercepts are the zeros; their sum is 9 and dividing by 3 gives the mean 3. Option 9 is incorrect because it is the sum, not the average (division was omitted). Option -3 results from a sign error, and 7 is just one of the zeros. Exam tip: read off the x-values from intercepts first, then compute average = (sum)/(count).
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Polynomials. Topic: Geometrical meaning of the zeroes of a polynomial..
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