If (y=85-5x), what is the value of (y) at (x=9)?
Answer and explanation
Correct answer: 40
Given \(y=85-5x\), substitute \(x=9\): \(y=85-5(9)=85-45=40\). Therefore, the correct value is 40. The value 45 is only \(5\times9\); it must be subtracted from 85. Exam tip: When evaluating a linear expression, substitute the given value first, multiply, and then perform addition or subtraction.
Frequently asked questions
What is the correct answer to this question?
40
Why is this the correct answer?
Given \(y=85-5x\), substitute \(x=9\): \(y=85-5(9)=85-45=40\). Therefore, the correct value is 40. The value 45 is only \(5\times9\); it must be subtracted from 85. Exam tip: When evaluating a linear expression, substitute the given value first, multiply, and then perform addition or subtraction.
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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