If a graph intersects the x-axis at (-3,0), (5,0) and (13,0), what is the mean (average) of these zeroes?
Answer and explanation
Correct answer: 5
The mean is the average of the x-coordinates of the x-intercepts:
\(\frac{-3+5+13}{3}=\frac{15}{3}=5\). So 5 is correct. Closest distractor D (15) is the sum of the zeros, not the mean; C (13) is just one root; B (−5) reflects a sign error. Exam tip: read the x-values of intercepts first, sum them, then divide by the number of zeros to get the mean.
Frequently asked questions
What is the correct answer to this question?
5
Why is this the correct answer?
The mean is the average of the x-coordinates of the x-intercepts:
\(\frac{-3+5+13}{3}=\frac{15}{3}=5\). So 5 is correct. Closest distractor D (15) is the sum of the zeros, not the mean; C (13) is just one root; B (−5) reflects a sign error. Exam tip: read the x-values of intercepts first, sum them, then divide by the number of zeros to get the mean.
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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