If (C(x)=180-9x) and (D(x)=120-3x), when will both be equal?
Answer and explanation
Correct answer: \(x=10\)
For the two values to be equal, \(180-9x=120-3x\). Rearranging gives \(60=6x\), so \(x=10\). Hence, the correct option is \(x=10\). For example, at \(x=12\), \(C(x)=72\) and \(D(x)=84\), so they are not equal. Exam tip: equate the two expressions first, then collect variable terms on one side.
Frequently asked questions
What is the correct answer to this question?
\(x=10\)
Why is this the correct answer?
For the two values to be equal, \(180-9x=120-3x\). Rearranging gives \(60=6x\), so \(x=10\). Hence, the correct option is \(x=10\). For example, at \(x=12\), \(C(x)=72\) and \(D(x)=84\), so they are not equal. Exam tip: equate the two expressions first, then collect variable terms on one side.
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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