If (A(x)=18+5x) and (B(x)=30+3x), when will both be equal?
Answer and explanation
Correct answer: \(x=6\)
For the two expressions to be equal, set \(18+5x=30+3x\). Subtracting \(3x\) and 18 from both sides gives \(2x=12\), so \(x=6\). Checking: \(A(6)=48\) and \(B(6)=48\). The nearby option \(x=5\) does not make the two values equal. Exam tip: To find when two linear expressions are equal, equate them first and solve for \(x\).
Frequently asked questions
What is the correct answer to this question?
\(x=6\)
Why is this the correct answer?
For the two expressions to be equal, set \(18+5x=30+3x\). Subtracting \(3x\) and 18 from both sides gives \(2x=12\), so \(x=6\). Checking: \(A(6)=48\) and \(B(6)=48\). The nearby option \(x=5\) does not make the two values equal. Exam tip: To find when two linear expressions are equal, equate them first and solve for \(x\).
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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