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If the polynomial \(p(x)=x^2-ax+12\) satisfies \(p(3)=0\), what is the value of \(a\)?
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Answer and explanation
Correct answer: 7
Substituting \(x=3\) in \(p(x)=0\) gives \(3^2-3a+12=0\), so \(21-3a=0\). Hence, \(3a=21\) and \(a=7\), making option C correct. Exam tip: If \(r\) is a zero of a polynomial, substitute \(x=r\) directly into the polynomial equation.
Frequently asked questions
What is the correct answer to this question?
7
Why is this the correct answer?
Substituting \(x=3\) in \(p(x)=0\) gives \(3^2-3a+12=0\), so \(21-3a=0\). Hence, \(3a=21\) and \(a=7\), making option C correct. Exam tip: If \(r\) is a zero of a polynomial, substitute \(x=r\) directly into the polynomial equation.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Polynomials. Topic: Polynomials in one variable.
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