If (p(x)=2x-5) and (q(x)=4x+1), what is (3p(x)-q(x))?
Answer and explanation
Correct answer: (2x-16)
Given p(x)=2x-5 and q(x)=4x+1, 3p(x)-q(x)=3(2x-5)-(4x+1)=6x-15-4x-1=2x-16. Hence, (2x-16) is correct. In (2x+16), the signs of the terms in q(x) have not been changed correctly while subtracting it. Exam tip: When a minus sign occurs before a bracket, change the sign of every term inside the bracket.
Frequently asked questions
What is the correct answer to this question?
(2x-16)
Why is this the correct answer?
Given p(x)=2x-5 and q(x)=4x+1, 3p(x)-q(x)=3(2x-5)-(4x+1)=6x-15-4x-1=2x-16. Hence, (2x-16) is correct. In (2x+16), the signs of the terms in q(x) have not been changed correctly while subtracting it. Exam tip: When a minus sign occurs before a bracket, change the sign of every term inside the bracket.
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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