If (p(x)=2x+a) and (q(x)=x-3), what is (a) if the zero of (p(x)+q(x)) is (1)?
Answer and explanation
Correct answer: 0
First add the polynomials: p(x)+q(x)=2x+a+x-3=3x+a-3. Since 1 is its zero, substituting x=1 gives 3(1)+a-3=0. Therefore, a=0. If a=-1, the value of the polynomial at x=1 would be -1, not zero. Exam tip: when a zero is given, substitute that value of x in the polynomial and set the result equal to 0.
Frequently asked questions
What is the correct answer to this question?
0
Why is this the correct answer?
First add the polynomials: p(x)+q(x)=2x+a+x-3=3x+a-3. Since 1 is its zero, substituting x=1 gives 3(1)+a-3=0. Therefore, a=0. If a=-1, the value of the polynomial at x=1 would be -1, not zero. Exam tip: when a zero is given, substitute that value of x in the polynomial and set the result equal 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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