If (p(x)=5x-4), what is the value of (p(3)-p(-1))?
Answer and explanation
Correct answer: 20
p(3)=5×3−4=11 and p(−1)=5×(−1)−4=−9. Therefore, p(3)−p(−1)=11−(−9)=20. The value 15 is only 5×3; it does not account for the constant term −4 or the value of p(−1). Exam tip: Use brackets when subtracting a negative number, since −(−9)=+9.
Frequently asked questions
What is the correct answer to this question?
20
Why is this the correct answer?
p(3)=5×3−4=11 and p(−1)=5×(−1)−4=−9. Therefore, p(3)−p(−1)=11−(−9)=20. The value 15 is only 5×3; it does not account for the constant term −4 or the value of p(−1). Exam tip: Use brackets when subtracting a negative number, since −(−9)=+9.
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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