Under which condition is one variable eliminated when two linear equations are added directly?
Answer and explanation
Correct answer: The coefficients of one variable have equal magnitudes and opposite signs
In option A, terms such as \(ay\) and \(-ay\) give \(ay+(-ay)=0\) on addition, so \(y\) is eliminated. Equal coefficients with the same sign require subtraction instead. Exam tip: check signs before choosing addition.
Frequently asked questions
What is the correct answer to this question?
The coefficients of one variable have equal magnitudes and opposite signs
Why is this the correct answer?
In option A, terms such as \(ay\) and \(-ay\) give \(ay+(-ay)=0\) on addition, so \(y\) is eliminated. Equal coefficients with the same sign require subtraction instead. Exam tip: check signs before choosing addition.
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..
