Which rule represents linear decay?
Answer and explanation
Correct answer: \(y=25-3x\)
A linear decay rule has the form \(y=a-bx\), where \(b>0\). In \(y=25-3x\), the coefficient of \(x\) is \(-3\), so \(y\) decreases by 3 for every increase of 1 in \(x\). \(y=18+4x\) represents linear growth because its coefficient is positive, while \(y=x^2-3\) is quadratic rather than linear. Exam tip: check whether the coefficient of \(x\) is negative to identify linear decay.
Frequently asked questions
What is the correct answer to this question?
\(y=25-3x\)
Why is this the correct answer?
A linear decay rule has the form \(y=a-bx\), where \(b>0\). In \(y=25-3x\), the coefficient of \(x\) is \(-3\), so \(y\) decreases by 3 for every increase of 1 in \(x\). \(y=18+4x\) represents linear growth because its coefficient is positive, while \(y=x^2-3\) is quadratic rather than linear. Exam tip: check whether the coefficient of \(x\) is negative to identify linear decay.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Linear growth and decay.
