If \(p(x)=x^2+4x+4\), how many real zeros are there?
Answer and explanation
Correct answer: One (repeated) real zero
The polynomial factors as \(x^2+4x+4=(x+2)^2\). Thus the only root is \(x=-2\), but it has multiplicity 2 — so there is one distinct real zero (a repeated root). Using the discriminant: \(\Delta=b^2-4ac=4^2-4\cdot1\cdot4=0\), which indicates a repeated real root. The closest distractor (A) is incorrect because \(\Delta\) is not positive, so there are not two distinct real zeros. Exam tip: check for a perfect square trinomial or compute \(\Delta\) to decide distinct/repeated/no real roots quickly.
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What is the correct answer to this question?
One (repeated) real zero
Why is this the correct answer?
The polynomial factors as \(x^2+4x+4=(x+2)^2\). Thus the only root is \(x=-2\), but it has multiplicity 2 — so there is one distinct real zero (a repeated root). Using the discriminant: \(\Delta=b^2-4ac=4^2-4\cdot1\cdot4=0\), which indicates a repeated real root. The closest distractor (A) is incorrect because \(\Delta\) is not positive, so there are not two distinct real zeros. Exam tip: check for a perfect square trinomial or compute \(\Delta\) to decide distinct/repeated/no real roots quickly.
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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