What will be the value of (y) from (5x+3y=14) and (2x-3y=7)?
Answer and explanation
Correct answer: \(y=-\frac{1}{3}\)
On adding the two equations, \(3y\) and \(-3y\) cancel: \(7x=21\), so \(x=3\). Substituting \(x=3\) into \(5x+3y=14\) gives \(15+3y=14\). Hence \(3y=-1\) and \(y=-\frac{1}{3}\). \(\frac{1}{3}\) can result from a sign error. Exam tip: add equations first when the coefficients of one variable are opposites.
Frequently asked questions
What is the correct answer to this question?
\(y=-\frac{1}{3}\)
Why is this the correct answer?
On adding the two equations, \(3y\) and \(-3y\) cancel: \(7x=21\), so \(x=3\). Substituting \(x=3\) into \(5x+3y=14\) gives \(15+3y=14\). Hence \(3y=-1\) and \(y=-\frac{1}{3}\). \(\frac{1}{3}\) can result from a sign error. Exam tip: add equations first 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..
