If (x+y=9) and (y=4), what is the value of (x)?
Answer and explanation
Correct answer: \(x=5\)
Given \(x+y=9\) and \(y=4\), substitute 4 for \(y\) to get \(x+4=9\). Subtracting 4 from both sides gives \(x=5\). Therefore, option C is correct. If \(x=4\), the sum would be 8, not 9. Exam tip: after substitution, perform the same operation on both sides to isolate the unknown.
Frequently asked questions
What is the correct answer to this question?
\(x=5\)
Why is this the correct answer?
Given \(x+y=9\) and \(y=4\), substitute 4 for \(y\) to get \(x+4=9\). Subtracting 4 from both sides gives \(x=5\). Therefore, option C is correct. If \(x=4\), the sum would be 8, not 9. Exam tip: after substitution, perform the same operation on both sides to isolate the unknown.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Pair of Linear Equations in Two Variables. Topic: Algebraic methods: Substitution method and Elimination method..
