If (A(x)=10+4x) and (B(x)=20+2x), when will both be equal?
Answer and explanation
Correct answer: \(x=5\)
For the two expressions to be equal, set \(10+4x=20+2x\). Subtracting \(2x\) from both sides gives \(10+2x=20\), so \(2x=10\) and \(x=5\). Checking: \(A(5)=30\) and \(B(5)=30\). Option \(x=4\) is a close distractor, but it gives 26 and 28, which are not equal. Exam tip: To find where two linear expressions are equal, equate them first and solve for \(x\).
Frequently asked questions
What is the correct answer to this question?
\(x=5\)
Why is this the correct answer?
For the two expressions to be equal, set \(10+4x=20+2x\). Subtracting \(2x\) from both sides gives \(10+2x=20\), so \(2x=10\) and \(x=5\). Checking: \(A(5)=30\) and \(B(5)=30\). Option \(x=4\) is a close distractor, but it gives 26 and 28, which are not equal. Exam tip: To find where 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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