The zero of the linear polynomial (2x+b) is (4). What is (b)?
Answer and explanation
Correct answer: \(-8\)
Since \(4\) is a zero, the polynomial must have value \(0\) when \(x=4\). Thus, \(2(4)+b=0\), or \(8+b=0\). Therefore, \(b=-8\). If \(b=-4\), then \(2(4)-4=4\), not zero. Exam tip: Substitute the given zero into the polynomial and equate its value to \(0\).
Frequently asked questions
What is the correct answer to this question?
\(-8\)
Why is this the correct answer?
Since \(4\) is a zero, the polynomial must have value \(0\) when \(x=4\). Thus, \(2(4)+b=0\), or \(8+b=0\). Therefore, \(b=-8\). If \(b=-4\), then \(2(4)-4=4\), not zero. Exam tip: Substitute the given zero into the polynomial and equate its value to \(0\).
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Linear polynomials.
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