What is the value of (x) from (7x-5y=4) and (2x+5y=41)?
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Answer and explanation
Correct answer: \(x=5\)
Adding the two equations eliminates \(-5y\) and \(+5y\): \(7x-5y+2x+5y=4+41\). Thus, \(9x=45\), so \(x=5\). If \(x=4\), then \(9x=36\), not 45. Exam tip: add equations directly when the coefficients of one variable are opposites.
Frequently asked questions
What is the correct answer to this question?
\(x=5\)
Why is this the correct answer?
Adding the two equations eliminates \(-5y\) and \(+5y\): \(7x-5y+2x+5y=4+41\). Thus, \(9x=45\), so \(x=5\). If \(x=4\), then \(9x=36\), not 45. Exam tip: add equations directly when the coefficients of one variable are opposites.
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..
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