Which option has (y) increasing by (7) each time (x) increases and (y(0)=18)?
Answer and explanation
Correct answer: \(y=18+7x\)
In a linear expression \(y=a+bx\), \(a=y(0)\), while \(b\) gives the change in \(y\) for every increase of 1 in \(x\). Here, \(y(0)=18\) and the increase is 7, so \(y=18+7x\). In \(y=7+18x\), the initial value is 7 and the rate of increase is 18, so it is not correct. Exam tip: Substitute \(x=0\) to check the constant term quickly.
Frequently asked questions
What is the correct answer to this question?
\(y=18+7x\)
Why is this the correct answer?
In a linear expression \(y=a+bx\), \(a=y(0)\), while \(b\) gives the change in \(y\) for every increase of 1 in \(x\). Here, \(y(0)=18\) and the increase is 7, so \(y=18+7x\). In \(y=7+18x\), the initial value is 7 and the rate of increase is 18, so it is not correct. Exam tip: Substitute \(x=0\) to check the constant term quickly.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Linear growth and decay.
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