If a parabola cuts the x-axis at (-1, 0) and (5, 0), how many real zeros does it have?
Answer and explanation
Correct answer: Two
Points where a parabola meets the x-axis are its real zeros. Two distinct intersections therefore mean two distinct real zeros; here the zeros are x = -1 and x = 5. Option B (one) would correspond to a tangent (a repeated root), option C (none) is impossible because intersections are given, and option D (three) is impossible for a quadratic since a parabola (degree 2) can have at most two real zeros. Exam tip: Count x-axis intersections for real zeros; for quadratics the maximum is 2 and a single intersection implies a repeated root.
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What is the correct answer to this question?
Two
Why is this the correct answer?
Points where a parabola meets the x-axis are its real zeros. Two distinct intersections therefore mean two distinct real zeros; here the zeros are x = -1 and x = 5. Option B (one) would correspond to a tangent (a repeated root), option C (none) is impossible because intersections are given, and option D (three) is impossible for a quadratic since a parabola (degree 2) can have at most two real zeros. Exam tip: Count x-axis intersections for real zeros; for quadratics the maximum is 2 and a single intersection implies a repeated root.
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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